trail pipe

Perhaps you should contact the engine builder of your choice and ask their professional advice. Asking what's the best pipe is like asking what's the best color.... everyone's going to have an opinion and there STILL won't be a consensus... You'll end up with about 8 different answers for 8 different reasons.

I can tell you GENERALLY, right bend pipe sacrifice a lot of torque (down low) for more HP (up high). Left bend pipes (stock shape) are the opposite. They are GENERALLY limited on top but give good torque.
 
Super noober's gonna say power pros, Awk'll say F7, Kgibson will say FMF, and I'll say procircuit. There, we've covered 4 pipes already and they're all different and each person will say that that pipe's the best because they like them.

Opinions are like buttholes, everyone has one and most of them STINK!

Edit: oh, Cole454 will say toomey....there, we've covered 5