I only have one F1 in my garage. Basically, if it aint broke, dont fix it. The only thing I did do, was adjust the gears.
for the track in question, ajust auto setting until you find the highest setting that has the car bouncing off of the rev limiter at the end of the straightaway.
then, in each individual gear, put first gear at the lowest number it will go to, put the top gear at the highest number it will go to.
adjust the gears in between for a smooth average.
then find the final drive ratio that you need by testing the car on the track. If your top gear will hit the rev limiter if the straight was 10 feet longer, you got it. watch what each gear does. If your car spends too long in any given gear, adjust it to a higher number. If your car seems to skip a gear, adjust that one to a lower number. Just play with them for a while, follow these basic tips, and soon you will come up with an even better method for gear tuning.