Wrong section man, but I'd say save up a bit more and get the BMW 540 (E39). None of the above you listed are really that popular with tuners, so therefore not many mods that get "high horsepower." What I mean by that is, you can do anything on your own, but there aren't many, if any at all, "bolt on" kits. Stillen has a SC kit for the Maxima, but you have to get the timing from the 3.0, don't know much about the others.