i agree with torque = short

but it does not end there, obviously.

i have a Losi Aftershock that came with a long fat pipe. they call it a tuned-pipe.
But man does that pipe sucked. no bottom, no top, no middle. The pipe was just killing the engine.

Then i swaped it out for a HPI polished pipe, which is about the same lenght, about the same diameter, but has a real tuned pipe shape.

Man what a differance. The Aftershock now runs like theres no tomorrow. Huge bottom, huge middle, and very good top. Its bassicaly not the same truck anymore.

So, my point, for newbies of course, dont take for granted that a short pipe will give you bottom end and that a long one will give you top end. Ask the guys arround before you buy. The internal construction is the major point there and usually, what you see of a pipe (the exterior) is just the exterior, nothing to do with the performance.

My 2 cents.