a wise man once told me:

"if you want a fast car, buy a fast car"... i.e. if you want something that will go fast, it really helps to start with something that will go fast right out of the box...

i would imagine that also applies to trucks... want a real pavement burner? start with something like a x5... the dynamics of the xterra don't exactly lend themselves to high speed chases... imo, a high powered xterra would be a recipe for disaster, unless really significant modifications were made to the rest of the truck...

one man's opinion anyway... but then again, i'm not a member of the "more power is always good" club...