If a Pro2 is quicker than your Pro4..You have some problems with your Pro4..
On the Belt vrs. Shaft question,For me a shaft drive car is just quicker out of the corners,I like a shaft driven car in stock but I dont(or in this case cant..
) drive a shaft drive car in mod.For me a belt car puts the power down alot smoother,It's alot easier on your car(as in You DONT break gears..
)The cars I'm comparing are Pro4,Alex R3,TC4,Evo4,XrayFK04,Shuie Mi2,415,Tech MY02R.I "test"(i think it's called play..
)at least 4 days a week..