I just use my normal racing gear ratios.. well.. if u find ur car revs really low u might wanna tune them a little tighter. but if you find you have to shift too much you might want to tune the car for higer speed.
stock gears with the 3rd gear higher and 5th lowered. but thats for any thing below 350hp.and GT2 so i have no say in this so ill go sulk in my corner with my GT2 disk in my hand