i know this may be completely absurd or just totally out there..

but i guess it all has to do with weight distribution. if the power comes from the front of the truck and is transferred to the rear of the axles, you would want that power to move to the ground as quickly as possible. assuming the power also moved through the chassis, and with gravity being a factor, its not saying you would want the truck as low as possible, but i guess more evenly aligned with the drivetrain. so that when you actually hammered down, the power would be distributed to the ground through the chassis faster because its not going in an upward motion. plus it would look cool too.

ok i totally think thats all bullshit, but i gave it my best. hope you can make some kind of sense out of my jumbled mess of words