The 2012 IPL G Coupe represents many things to Infiniti. For starters, the Infiniti Performance Line (IPL) is the automaker's first dabble into the kind of performance premium sub-branding that makes German luxury cars bearing an "//M" or "AMG" badge so alluring. If the automaker deems the IPL G a success, then perhaps we'll see the sub-brand expand. Could an IPL M Sedan be on the horizon? Let's first figure out if the IPL G Coupe in the CNET garage is worth the extra dough.
Stepping up to the IPL G Coupe really only improves the G37 Sport in two measurable ways: it goes faster and it handles more sharply. The other changes, including a more raucous exhaust system and bright red leather sport seats, are more subjective improvements, but welcome additions nonetheless.
It goes faster.
We start our trip around the upgraded IPL G Coupe in the engine bay where, aside from the chrome IPL badge on the engine cover, not much is different from a standard G37. Yep, that's the same 3.7-liter VQ37VHR engine. However, what you don't see is that thanks to a few ECU tweaks, Infiniti's engineers have managed to squeeze an extra 18 horsepower out of this mill. Now the VQ37HDR outputs 348 horsepower and twists its crank to the tune of 276 pound-feet of torque.
That torque number is only up by a scant 6 pound-feet, which may explain why the IPL G Coupe doesn't feel madly different from a G37 Sport. Zero to 60 takes about 5.0 seconds, just 0.2 seconds faster than the non-IPL model, which really makes any drag race between the two more of a driver's race than a hardware comparison. You'd really have to approach triple-digit speeds to feel any real difference between this and your neighbor's G37S.
You wouldn't need to do more than idle the engine to hear the difference. One of the most visible and audible upgrades the IPL G Coupe gets is a throaty exhaust system with larger dual tips. If you're like me and look back fondly on the fantastic rumble that the old G35 and 350Z had at idle and the exotic sounding howl of their 3.5-liter engines at full bore, you're in for a treat when you
turn over the ignition push the start button in your new IPL G Coupe, because the growl is back.
Firing off downshifts with the seven-speed automatic gearbox as I approached every traffic light triggered a rev-matching blip of the throttle and a satisfying bark from the new exhaust. And as I pulled away from each light, that same exhaust note was usually incentive enough to hold onto each gear for a few more revs and maybe open the throttle up just a bit more. Admit it, maybe 50-percent of the reason that most people buy a performance premium variant of any car is because they want to feel like a racecar driver. The IPL's exhaust goes a long way toward creating that illusion.
I mentioned in passing that our IPL G Coupe was equipped with a seven-speed automatic transmission. This is a perfectly passable gearbox, but it's got nothing on the dual-clutch automated manual gearboxes present in BMW's performance offerings. If you're looking for the best performance from the IPL G, you'll want to save a few bucks and spec the six-speed manual gearbox. If you only signed up for the exhaust note, the rev-matching seven-speed auto will work just fine.
Infiniti's gearbox features a manual shift mode, with some of the nicest paddle shifters in this segment, however the lag between a paddle input and engagement of the next gear restricted the manual shift mode's value to preselecting a lower gear for a freeway pass or forcing the transmission to hold a single gear through a twisty passage. For all other situations, just leave it in automatic Sport mode and let the rather capable computer do the shifting.
It handles better.
Tucked into the IPL G Coupe's wheel wells are large 19-inch aluminum alloy wheels shod in grippy 225-width tires up front and 245-width tires out back. Twenty-percent stiffer springs suspend the vehicle over these upsized rollers. Stiffer springs usually beget a stiffer ride, but thanks to tweaks that have been made to the IPL G Coupe's dampers, the sports coupe doesn't feel dramatically more bone-jarring over low-speed bumps and cracks than a standard G37 with the Sport package. You may recall that we Car Tech editors were of split minds as to whether the standard Sport package's ride is too harsh to begin with, but at least in this case the rougher ride matches the IPL's racy character.
While the IPL doesn't feel much different from the standard G37 while moseying around town. I discovered on a windy road that its handling limits feel noticeably higher than more mundane Gs. Moreover, those limits are approached, met, and -- if you're not careful -- exceeded in a much more predictable and controlled manner than the standard G Coupe as well.