From the back of the G8, you...
From the back of the G8, you get a sense of the agility and power it possesses. The taillights are tasteful and modern and the twin-dual exhaust tips make a statement of performance.
Comfort was certainly one of the great focuses for each occupant. With five adults in the G8 GT, there wasn't any mention of discomfort or lack of space. One passenger even said, "This is the first car in which I could actually see myself taking a long trip in the backseat." Since the G8 actually has four doors, ingress and egress are easy, too. This may come as a welcome feature to any GTO owner who has grown tired of waiting for the pseudo-luxury electronic seats to move to provide access to the backseat. Both the passenger and driver seats are well constructed, but lack the side bolstering needed for heavy cornering. We expect this will be taken care of when the GXP model hits Pontiac showrooms in late fall 2008.
Performance
Turn the key and the 361-horse L76 fires to life with a smooth and muted statement from the tailpipes. While the engine wails out a sweet song under heavy acceleration, it's whisper-quiet at cruise. The L76 uses Active Fuel Management, which cuts off half the cylinders at various points to increase fuel economy. It engages seamlessly and disengages almost instantly, making it hard to notice. We experienced around 17 mpg, combining our testing, heavy street use, and highway mileage. Not too shabby, especially considering that this is a full-size sedan propelled by a powerful V-8.
Much of the great gas mileage can be attributed to the mild 2.92 rear gear and six-speed automatic transmission. It's very easy to lower these numbers in a hurry, though. Move the shifter over to the right to engage Sport mode, which will raise the shift points and make the G8 more sensitive to downshifting. If you feel a little more spirited, you can put the shifter into Manual shift mode. This will allow you to decide when you want to go into the next gear, and will even blip the throttle on a downshift. Don't expect this to deliver lightning-fast shifting, though. The delay from driver input to gear selection was about half a second, a far cry from its European competitors.
We were able to take the G8 GT out to a local NHRA dragstrip and perform acceleration and quarter-mile testing. With the shifter in Sport and the traction control system disengaged, the muscle sedan rocketed to 60 mph in 5.6 seconds (as tested on our G-Tech Pro RR) and through the quarter-mile in 13.8 at 101 mph, according to the track's timing equipment. We tried several different launching methods, but found that rolling onto the gas after flashing the converter up to about 1,500 rpm was the most effective. We experienced wheelspin if we simply hit the gas when the tree dropped, and flashing the converter too high resulted in the G8 pushing through the brakes...and the staging beams.
A great amount of torque management was felt as we approached each shift. It was like the car was laying down before each gear change. We felt it kick in around 5,200 rpm. Thankfully, this is something that can be taken out with a PCM tuner, and we suspect the G8 GT will be able to post consistent mid- to low-13-second passes with a bit of tinkering in the tune.
 The L76 V-8 engine produces...  The L76 V-8 engine produces 361 hp at 5,300 rpm and 365 lb-ft at 4,400 rpm. The peak power rpm rating is a little low compared to the traditional high-spinning LS-series engine before it. Since it's LS-based, that means making more power will be very simple. The battery is located in the trunk to clear up the engine bay and also distribute the weight a little more evenly. |  Our test vehicle wasn't equipped...  Our test vehicle wasn't equipped with these optional 19-inch aluminum wheels that come with the sport package. Both sets of wheels look nice, but the 19s are easily the most handsome. (This G8 GT belongs to Tom Tiberio.) |  Attached to the front strut...  Attached to the front strut is the endlink for the 23mm swaybar that ties both sides of the suspension together and limits body roll. |
In its current state, however, it felt too tame and too smooth. Because of this, it feels like we didn't really experience the G8 GT's full potential. There was no grit to it when we mashed the go pedal; it just moved out with a heavy feel. Yet on the flip side, it did post impressive numbers.
On the backroads, the brilliant four-wheel independent suspension worked well. The MacPherson struts and rear coilover shocks did a fair job of absorbing the road imperfections and the grip was phenomenal from the 245/45R18 Bridgestone Potenza Summer tires. We tossed the G8 GT through a series of tight corners and the responsive steering never failed to impress with its crisp feedback.
Body roll, however, was pronounced when we threw the GT's massive weight hard into a corner. The sway bars did a fair job of controlling the weight transfer, but there is room for improvement.