I'm not a tuning Guru, but I've found a spec that works for me:
Aerodynamics: Add a Wing,max front, back
[B]Engine:[/B] Buy all the bits, don't forget the supercharger!
Transmission: 420 Km/h or 260ish Mph, the car puts out so much torque and the tires only have so much grip that going with any shorter gearing won't make you go that much faster.
LSD: 10/60/10 - The diff makes a huge difference in this car, so you can come here to tailor it too your style
Suspension:
Ride Height: -25/-25
Spring Rate: 19.8/17.3
Dampers (Ext) : 8/6
Dampers (Comp) : 8/6
Anti-Roll Bars : 5/5
Camber : 4.0/2.5
Toe : 0.00/0.00 - Note I really hate toe, so does Bob, so feel free to change this
Brakes : 5/5 for Racing Soft, 4/4 for Sports Soft
Aids :
All off except for ABS 1. The Speed 12 will understeer while breaking if you don't use ABS.