800hp+ single turbo truck is extremely fun to drive and scary as ever when the turbo lights! LOL!!!Gearing, altitude, tire size, axle ratio all contribute greatly.
Compounds 64/s480 will support 800hp, could go smaller depending on altitude.
A single turbo at 800hp is not going to tow well, but would be fun to drive
s300 based turbos will support 700+ hp. To get to 800hp is a big jump.