The Good: Toned-down exterior styling; simplified iDrive interface; adaptive headlights and pressure-sensitive taillights; valve-controlled throttle. The Bad: Limited Bluetooth phone compatibility; pricey; run-flat wheels make for a bumpy ride. The Bottom Line: Very little bad can be said about the BMW 330i. Its first-rate technology contributes to performance, comfort, and safety. 2006 BMW 330i SedanSince the introduction of the 320i in the late 1970s, the BMW 3 Series has been the benchmark car in the compact sports luxury class. The fifth generation of the 3--internally code-named E90--recently debuted, not only leveraging technology from its larger and more-expensive siblings but also introducing important features of its own. Underneath new styling that is influenced by, but toned down from, recent BMW offerings, all-new in-line six-cylinder engines improve upon the Valvetronic variable-valve-timing system introduced in the latest BMW V-12 and V-8 engines. Suspension and optional steering systems are the next-generation derivatives of those found in BMW's larger sedans. The 2006 3 Series is slightly larger than its predecessor in almost every dimension for greater passenger and trunk space, but weight has increased by less than 100 pounds, partially because of the design and from the use of lightweight materials. Both 325i and 330i models are offered. While previous BMW numeric designations went by engine size, the new American-spec 3 is different in that engines for both models are of 3.0-liter displacement. The 325i has 215 horsepower and 185 pound-feet of torque; additional features boost the 330i to 255 horsepower and 220 pound-feet. Both have a ULEV2 low-emissions rating.Our test car was the 2006 BMW 330i. With a base price of $36,300--plus $1,000 for the Cold Weather Package, $2,200 for the Premium Package, $1,275 for the six-speed Steptronic automatic transmission, $2,000 for the navigation system, $595 for Sirius satellite radio, and $695 for the destination charge--it was a healthy $44,540 worth of BMW.The styling of many recent BMWs has been, to put it mildly, controversial. Although the styling trends introduced for the 7 Series and developed for the later 6 Series coupes, 5 Series sedans, and the Z4 Roadster can be seen in the sharp, angular accent lines on the 2006 330i's hood and at its belt line, as well as in the high, well-defined trunk, the overall shape is not too far removed from that of the previous generation. It's much more evolutionary than revolutionary. We received mixed comments from onlookers, with more favorable than not. The 2006 BMW 330i's interior design and comfort only reinforces BMW's reputation. It's slightly roomier and quieter than before, and it has more of a luxury car character. Front-seat comfort is first-rate. Rear-seat space is marginally increased and good for the size of the car, but it is still a relatively small vehicle. Nighttime access is helped by interior courtesy lighting and small external spotlights in the front-door handles. As is increasingly common in luxury cars, there is no conventional key. The remote-access fob is inserted into a slot in the dashboard. To start the car, you can press the Start button, and you can press it again to stop the engine.If the GPS navigation system is specified, the much-copied, cockpit-style instrument panel favored in earlier BMWs is replaced by a twin-brow design. The usual brow shading the main instruments is joined by a similarly shaped one directly to the right, which very effectively shades the nav system's LCD screen. It is easily visible in all lighting conditions, even if the driver is wearing polarized sunglasses. The iDrive knob twists and moves on all axes, allowing control of the car's functions.The climate, communication, navigation, vehicle information, and audio system displays are all controlled through the big iDrive knob on the console. When compared with BMW's recent styling, perhaps even more controversy has been created by iDrive here, but the system has likewise been simplified and improved since it debuted in the 7 Series in 2002. Categories, menus, and actions are selected by a combination of fore, aft, and sideways motion; twisting; and a mouselike click of the iDrive control. For anyone with experience using computer and consumer electronics interfaces, the iDrive learning curve should prove to be reasonable. Most functions and required actions are very logical.Interestingly, the iDrive control is context sensitive. If there are four selections on a menu, it can be turned to four positions--then it stops. If there are three selections, it can be turned to three; if there are five, you have five positions. A touch of the menu button next to the iDrive control resets the system back to the main menu at any time. Although address entry--one character at a time--is as annoying as with many other systems, it's possible to zoom the display out, move the reference position to your destination, and click the iDrive control to set a destination. As with other nav systems, it's safest to use when stopped or when the front passenger can control it. Any intended route is displayed well on the map, with additional visual and auditory instructions. The main navigation screen displays an easily understood menu.BMW knows its popularity in the tech world and has a host of standard or optional information, as well as entertainment features, beyond the navigation system. Bluetooth connectivity is part of the Premium Package, although we were unable to pair it with either a Motorola V505 or a Palm Treo 650. Most BMW CD players and changers are MP3 capable, although, because our 330i came with the navigation system, a center-installed remote changer was required for MP3 CD capability. There is an auxiliary input for portable audio devices, and Sirius satellite radio is available. And for the ultimate in drink cooling, check out the air-conditioned cup holder in the center console. Outside, adaptive taillights vary in intensity according to brake effort, and adaptive Xenon headlights turn with the steering wheel for improved nighttime visibility.Although the iDrive system seems high tech, it pales in comparison with what's under the hood. The 2006 BMW 330i's engine is an in-line six-cylinder, a design with fine dynamic-balance characteristics and smooth, even torque pulses. If its four valves per cylinder and dual overhead cams are conventional by today's standards, that's about where convention stops. The engine's cylinder head and cylinder-water jacket are cast in aluminum alloy, but the upper and lower crankcase assemblies are cast from magnesium alloy for light weight. BMW's Valvetronic system uses variable-leverage rocker arms between the intake cam and the intake valves to vary valve lift. That and fuel-injection mapping also replace the traditional throttle--all engine speed is controlled by valve lift changes. Cam phasing is, as before, varied by the VANOS system on both intake and exhaust cams. The 330i engine has a three-stage variable induction system rather than the two-stage intake of the 325. This allows further fine-tuning of power delivery. Higher-pressure fuel injection for better fuel atomization and new engine-management electronics top it off. Other innovations, including an electric coolant pump and variable-volume oil pump, further improve efficiency.The result is an engine that, while more complex than last year's 3.0-liter six-cylinder, is significantly lighter, more powerful, cleaner in emissions, and more fuel efficient. Horsepower is up from 225 to 255 at 6,600rpm, while torque has increased from 214 to 220 pound-feet at a low 2,750rpm. Redline is up to 7,000rpm from 6,500. Power delivery is smooth and even, with good low-end torque and strong midrange power. It does not run out of breath as it nears redline. Our test car had the optional six-speed automatic transmission, which rates an adequate EPA 21mpg in the city and 29mpg on the highway. Acceleration is controlled via valve lift changes and fuel injection. The engine's torque band is wide enough that precise gear choice would not be a problem even with a manual, and the six-speed automatic's closer ratios decrease engine speed changes when shifting. The automatic works well enough for everyday driving but shifts sedately at part throttle. For performance driving, the shift lever can be placed in Steptronic mode for manual control. This is preferable for quickest acceleration and on appropriately twisty secondary roads, but shifting, particularly downshifting, is still relatively slow.The chassis has been upgraded as well. The structure is lighter and more rigid than in the previous model. Double-pivot front suspension, as previously used in larger BMWs, sees its first use in the 3 Series. It makes extensive use of aluminum to decrease unsprung weight and improve handling and responsiveness. There is a new five-link suspension at the rear for more precise wheel control. Both front and rear suspensions are mounted to solid but well-insulated subframes to decrease transmission of road noise into the passenger compartment. Speed-sensitive power steering is standard, with the Active Steering system previously offered on the 5 Series and 7 Series available. Larger vented brake discs are found at all corners. Our test car had the standard-suspension calibration. Its springs and shocks are relatively soft, offering good ride comfort on smooth surfaces or gentle undulations, but the ride is compromised on sharp bumps by the sidewall stiffness of the standard run-flat tires. Although the steering effort may seem heavy, especially at low speeds, it imparts a feeling of security at higher speeds. Cornering behavior with the standard suspension is up to BMW's high standards, but if sportier driving is in your plans, a sports suspension with stiffer springs and shocks, as well as larger wheels and tires, is available. On the highway, the fine chassis and clean aerodynamics give the 330i a solid, stable, and quiet ride.The 2006 3 Series structure was designed to meet or exceed all safety tests and standards worldwide. To do this, different materials, including high-strength steel, are used in varying locations of its unibody structure. That structure was designed to transfer impact forces around the passenger cabin for maximum occupant safety. Dual front and front-seat-mounted side air bags are standard, as are front and rear side Head Protection System air bags. There are no rear side air bags--BMW says they are not needed due to the head air bags and side structure. The newest generation of BMW's Dynamic Stability Control (DSC) is featured in all 2006 3 Series models. In addition to the traction control and stability-enhancement functions of previous DSC systems, it compensates for brake fade by increasing hydraulic pressure when brake temperatures rise. When the throttle pedal is abruptly released, the brake pads are pressed snugly against the rotors in preparation for braking. This decreases braking reaction time. Similarly, when the standard windshield-wiper rain-sensing system detects moisture, the brake pads are periodically brought just close enough to the rotors to wipe away any water film for better braking performance when it is needed. Start-off Assistant helps hold the car when it is stopped on a hill.Run-flat tires are standard for all models, with a flat-tire warning system. All DSC functions remain enabled if a tire loses air pressure. The space under the trunk floor once used for a spare tire is now available for storage.