The Good: The 2008 Porsche Cayenne GTS is the finest-handling SUV we've ever tested, yet still retains off-road capability. Its Bose audio system produces clean and refined sound. The Bad: The Porsche Communication Management option, a unit combining navigation, stereo, and phone, represents older cabin tech. Its phone system is designed for Europe and doesn't work in the U.S. The Bottom Line: It may cost a lot, but the 2008 Porsche Cayenne GTS is a high performance on- and off-road vehicle. Current cabin tech isn't great, but a new version of the Porsche Communication Management system is coming out soon. Photo gallery:2008 Porsche Cayenne GTSThe first clue that the 2008 Porsche Cayenne GTS isn't like other SUVs is the shifter, which works the six gears in a manual transmission. Another clue comes when you get it in the twisties, and feel its utter lack of roll in hard cornering. The Cayenne GTS offers the most sports car-like handling of any SUV, even surpassing the BMW X5 in this regard. We've heard comments around the office that the Porsche badge shouldn't be this high off the ground, but purism aside, our friendly neighborhood Porsche rep tells us that the Cayenne sells, giving the company a stable bottom line with which it can work on better and better 911s. OK, we can accept that it's all for the greater good. Although the transmission might be a little low-tech, the engine and suspension make up for it. The air suspension features all sorts of tricks to morph the Cayenne GTS from high-clearance, all-terrain vehicle to road-hugging canyon carver. Cabin tech is also present in the form of the Porsche Communication Management system, an all-in-one navigation, stereo, and phone unit--only, the phone part doesn't work in the U.S. Fortunately, this version of the system is on its way out, soon to be replaced by a whole new system featuring better controls and Bluetooth. Test the tech: Ride quality Behind the shifter on our 2008 Porsche Cayenne GTS is a bank of controls for the suspension almost as confusing as the acronyms they control. This car came with PASM, or Porsche Active Suspension Management, and PDCC, which stands for Porsche Dynamic Chassis Control. A rocker switch on the left moves the car from on- to off-road driving modes, with different levels of differential lock. A big button, labeled Sport, sharpens the throttle response, while three buttons to the right of that let you choose Comfort, Normal, and Sport modes for the suspension. Another rocker switch beyond those changes the ride height of the Cayenne GTS through three different modes. The Cayenne GTS gets a complex set of controls to adjust the suspension.To test out these different suspension settings, we found a section of rough pavement in San Francisco, approximately 100 yards long, and drove over it five times at 30 mph, each time with the suspension on a different setting. For our first run, we wanted to establish a baseline, so we put the suspension into Normal mode and called the ride quality zero. For a rougher ride from the other settings we subtracted numbers, and we added numbers for a smoother ride. In Normal mode, the Cayenne GTS wasn't floating over the rough bits, transmitting jolts from washboard surfaces and potholes. Getting back to the start, we pushed the Comfort button and prepared for an easy ride. But our editors couldn't feel much difference between Comfort and Normal. Jolts were still transmitted to the cabin, from the repetitive bumps of the washboard section to the harder jolts of the potholes. The Cayenne GTS gained no points for this setting. Putting it in Sport mode, we repeated the course, this time finding a noticeably harsher ride. The jolts were delivered with more force, as this setting also keeps the Cayenne GTS flat in hard cornering. Editor Wayne Cunningham gave it a -3 for ride quality, while Antuan Goodwin wrote down a -2. But, we weren't done yet. The Cayenne GTS has three ride heights controlled by another switch. The highest level, which Porsche specifies for special terrain, can only be used below 19 mph, but the second highest level can be used at greater speed, and is for light off-roading. We put it in this mode and ran the car over our course. We felt better damping than with the Comfort mode, as there was more travel in the suspension, letting it absorb more of the jolts. Both editors awarded the ride quality with a +2. We came up with qualitative ratings for the smoothness of the Cayenne GTS' ride.This air suspension can also lower the car, with the lowest setting dubbed Loading Level by Porsche, as it's designed for easily getting cargo into the car. Like the highest setting, you can't drive over 19 mph down this low. The second-lowest setting is for sport driving, so we used this to take our final run over the road. Our editors noticed an even rougher ride than with the Sport setting alone. The imperfections of the road delivered a particularly jarring ride, and our editors gave the ride comfort a -5 and a -4, respectively. Although a very expensive SUV with fine materials in the cabin, the Cayenne GTS doesn't deliver the comfortable ride of a luxury car, not even with the adjustable suspension. However, it really does hunker down, with the air suspension and controls bringing noticeable changes to the sports settings. In the cabin The cabin of the 2008 Porsche Cayenne GTS is fitted with an Alcantara roof and pillar liner, and leather and suede seats. Our vegetarian photographer said of the seats that it is as if you can feel both the outside and inside of the animals they come from; but, there isn't a cloth option for the PETA crowd. Porsche throws some silver-colored trim, panels, and switchgear around the cabin, which unfortunately has a cheap, plastic feeling. The Porsche Communication Management system has a simple knob for browsing and selecting menu options.But, cabin tech is what we are here to talk about, and this Cayenne GTS came fitted with the Porsche Communication Management (PCM) option. As mentioned above, the PCM encompasses navigation, stereo, and a phone system. The interface for this system isn't particularly intuitive, and it adds a lot of black plastic buttons to the cabin. A lot of the system is controlled by a simple black knob that lets you select from context-sensitive menus. Spelling street and city names with this knob can be tedious, and there is no voice-command option. Porsche is in the middle of transitioning from PCM 2.0 to 3.0, with the new system offering hard drive-based navigation and other, more modern, electronics. The navigation system performs the basics, but its only advanced features are a trip planner, which lets you enter multiple waypoints, and a detour button, useful for changing your route on the fly. The points-of-interest database is somewhat limited, with mostly travel-oriented locations, such as recreation areas, gas stations, and restaurants. The route-guidance voice is on the strident side and doesn't do text-to-speech. While under route guidance, we found that the position of the car on the map occasionally trailed the actual position by enough for us to miss a turn. The stereo uses the same interface as the navigation system; the same knob lets you browse MP3 CDs and XM satellite radio channels. Although not present on our car, you can option in Porsche's Universal Audio Interface, which adds a USB port and iPod integration, as long as the PCM is also present. PCM 3.0 will also include the option for a six-disc changer. The optional Bose Surround-Sound system uses 14 speakers around the cabin.Our car also came with the Bose Surround-Sound option, which places 14 speakers around the cabin, powering them with a 410-watt amp. We found this system produced a very balanced sound--not too heavy on the bass and not bright on the treble. In general it was clean and unobtrusive, sounding great with symphonic works, but not really the kind of system that's going to get the car thumping from hip-hop. The phone system in the PCM 2.0 is a legacy from Europe, and doesn't work with U.S. cell phones. Similar to what we saw on the Maserati GranTurismo, you need to insert a compatible GSM SIM card into the PCM. The functionality is supposed to include texting, along with hands-free calling, and we assume access to any contacts stored on the SIM card, making it all the more bittersweet that it doesn't work here. Good thing that PCM 3.0 will include a Bluetooth option, although we don't know its capabilities yet. Under the hood We were expecting the acceleration on tap from the 4.8-liter V-8, an aluminum engine block with four overhead camshafts and Porsche's Variocam variable-valve timing. The pleasant purr of this engine makes it sound finely tuned, and the specs show 405 horsepower at 6,500rpm--an increase of 20 horsepower over the standard Cayenne--and 369 foot-pounds of torque at 3,500rpm. Porsche claims 5.7 seconds from 0 to 60 mph. The V-8 engine makes a pleasing sound when the revolutions are up.The Porsche Cayenne GTS surprised us with its capability in hard cornering. The Cayenne GTS sits lower than its siblings by about an inch, and the air-suspension settings let you bring it down further. As we dove into corners on a winding mountain road with the various sports settings on, we were impressed with the sports car-like feel of the Cayenne GTS. Although we had a sense of its bulk, it stayed very flat in the corners, and its all-wheel-drive helped it keep traction as the g-forces increased. The steering was very responsive, as we would expect from a Porsche. For sport driving, the six-speed manual was a bit of a let-down. The long shifter doesn't make for quick shifts, although the ratios let you leave it in third on curving roads. In freeway and city driving the Cayenne GTS was well-mannered. It has a hill-hold feature that helps keep the car from rolling with the manual transmission. Because of the horsepower and torque, you'll have to learn to make smooth shifts--during our week with the car each shift meant a powerful punch in the back. It's not every day we see a manual stick in an SUV. In fact, this is the first time we've seen one.Although we didn't take it off-roading, Porsche claims it can handle rough terrain. The air suspension takes it from a ground clearance of 6.4 inches up to 9.9, and it has a fording depth of 21 inches. The electronic center differential has varying levels of lock, depending on the car's off-road mode. Porsche manages a ULEV II rating for emissions--an impressive number considering the size of the engine and its performance figures--but fuel economy isn't so hot, with 11 mpg city and 17 mpg highway in EPA testing. Our average with the car fell right in that range, coming in at a solid 13 mpg. In sum Our 2008 Porsche Cayenne GTS came in with a base price of $70,900. Significant tech options included in our test car were the Porsche Communication Management system, which includes the navigation system, for $3,300, and the Bose audio system, for $1,690. Some of the pricier non-tech items in our car were the GTS Red paint job, for $3,140, and the all-leather interior package, which adds $3,170. The total for our car, along with the $895 destination charge, racked up to $90,100. We would also have included the Universal Audio Interface, which brings in iPod integration, for $95, making it a no-brainer option. We were also amused by some of the other available options, such as $2,160 for leather air vents and $1,415 for carbon fiber, roof, grab handles. The BMW X5 and X6 are the closest competitors to the Cayenne GTS, both being performance-oriented SUVs. The Cayenne GTS performs a little better than the BMWs, but offers inferior cabin tech. In rating the Cayenne GTS, we have to give it a mediocre score for cabin tech. The stereo earns it points, and there are some things we like about the navigation system, but there's nothing particularly innovative here. For design, we like the exterior of the car, but the cabin tech interface isn't great, bringing down the total. Performance is where the Cayenne GTS shines, offering sports-car handling and off-road capability, only taking a hit for the very poor fuel economy.