6200 S3 Tires
7200 Semi-Racing Suspension
13000 Supercharger
5250 Polish
11000 Balance
1250 Chip
10200 Full Race Trans.
4600 Race Brakes
4600 Race Exhaust
1100 Weight Reduction 1
5300 Weight Reduction 2
4250 1.5 Way Diff
1000 Racing Flywheel
50 Oil Change (cheesy 5% power boost)
75000 Total
I did the fastest lap with the default suspension settings.
I forgot to get the gear ratios, will post later. I just used the little auto slider thing to adjust the whole set so it is about 500 rpm short of redline at the end of the "straight"
It's a pretty good car, has some understeer turning in, but you can neutralize it with trail braking and throttle.
It could use a brake controller and stiffer rear bar but no money left for that.

Good choice GTO, it's a fun car. Not a complete pig, and not a UFO even when modded heavily. It even has a real life road racing pedigree.