RKHiPerformance said:
Has anyone seen reliable information on wheel and tire upgrades that fit with no (or minimal) modifications?
Adding a 17x11" wheel & 315/35-17 tire to the back of my 2002 Camaro SS really improved the car's appearance, and I wonder if anything similar is possible on the GTO.
The simple answer to your question is NO. The key being you specified that you wanted "no (or minimal) modifications".
Now, if you are serious about rolling up your sleeves and getting after it, then you can put 295/35-19s in the back; or at least the boys at BMR were able to.
Here is the a couple of C&Ps of the text from their GTO buildup:
"At this point we felt it was necessary to address the look and stance of the car with a set of wheels and tires for the street. I am extremely picky when it comes to wheel/tire/wheelwell ratio and I knew the car needed to be lowered slightly so the first thing we did was install a set of our BMR lowering springs to lose about an inch of fender gap. Once the car was sitting at the proper height, we made a lot of careful measurements to have some custom wheels made for us by I-Forged. Our initial goal was to mini-tub the rear for a set of 345/30R19" tires but it's just not possible with the rear suspension layout. In the end, the wheels we ended up choosing are the I-Forged Aero's in a 18" x 8" front and a 19" x 10" rear. These take approximately 6 weeks to build which gave us plenty of time to prepare the car for them.
The wheels ordered for the rear had an extra 1/2" of width on the outside and an additional 1.5" on the inside so we began work on the wheelwells to accomodate them.
This involved notching the A-arms, sectioning the floorpan to move the wheeltubs over, and spacing the shocks inboard. We also decided at this point to upgrade the shocks with some 12 way adjustable QA1 Aluma Stars. Since QA1 does not make a shock for this application, we located one that was the correct overall length when compressed and machined an adapter to make it compatible (these shocks with the modified adapter are available through BMR).
All-in-all it took about 3 full days of work to modify the fenderwells but the end result was worth it as seen in the images below. Nothing beats the looks of a car with the right stance. Yokohama AVS Sports were used with a P295/35ZR19 on the rear and P245/40ZR18's on the front. We specifically chose a taller, 27.5" rear tire to give the car a slight rake and to attempt to visually shrink the rear quarter panel height. This also makes the car appear to be lower than it actually is.
To the hardcore drag race crowd, this mod may not be too appealing however if you follow along with the rest of the build you will see that the wheelwell mods pay off in the end."
Full article is at:
http://www.bmrfabrication.com/GTObuildup.htm