I find it a bit tricky with sharing tuning setups for Forza because there's typically a broad range of possible upgrades. A tuning setup for one configuration might not be remotely viable for a car with a totally different set of upgrades. You can take a low-end car and potentially heavily upgrade it to double or triple its original stock performance. You can take a Volkswagen Beetle and basically make it a Formula 1 car disguised as a Beetle. I personally prefer trying to keep cars somewhat close to original so some essence of the original car remains, but this isn't always plausible, like if you're in a car with 389 PI (Performance Index) and you're in a race against cars at around 600 PI. Even on a low difficulty setting, you're probably going to get crushed.
Still, I'll try posting a few, probably based on being upgraded with little more than what's necessary to actually tune it.
2003 Porsche Carrera GT
800 PI
3271 pounds
41/59 weight distribution
RWD
general tune
Tire Pressure: 30.0 front, 34.5 rear
Wheel Camber: -1.7 front, -1.3 rear
Toe: 0 front, 0 rear
Caster: 6.0
Anti-roll Bars: 18.3 front, 17.5 rear
Springs (pound/inches): 618.1 front, 907.5 rear
Ride Height: 40% front, 40% rear
Bump: 3.5 front, 5.1 rear
Rebound: 5.7 front, 8.2 rear
Roll Center Offset (inches): 1.2 front, 0.4 rear
Anti-Geometry: 26.9 front, 13.5 rear
Downforce: medium front, medium rear
Brake Balance: 50%
Brake Force: 100%
Rear Differential: 42% acceleration, 31% deceleration