im sure youve heard it all before but the gains to be had can be gained without changing teh intake tube or the maf. free upgrade: air silencer box. next upgrade, exhaust. cheap way and most power : run illegally, catless w/redone downtubes and replace the mufflers with glasspacks or be a really illegal bastard and run openheader. that might sound cool, actually. My 280ZX sounded bad (as in good-bad) as hell openheader, it sounded like a WWI fighterplane, loud, angry and unrefined
or go an easier way and redo your downtubes, weld in larger, freer flowing cats without bends in them, and replace the resonator and mufflers.
what I am considering doing is having the cats and downtubes spliced neatly out, and putting them aside for smogtime 2 years from now, since my resonator has already been upgraded to magnaflow and I figure the stock mufflers themselves cant be too restrictive, and I dont want to draw any more police atttention than I need to, so those I am leaving stock.
Just from having exhaust redone many people have gained as much as a second on ETs at the track on the 1/4, which is a HUGE improvement for such a simple mod, whereas intake modifications have had less dramatic results. I think it yields something like 25? hp. I could just be grossly exaggerating, but there is a substantial gain to be had for such an inexpensive (and engine-safety related) mod. The exhaust now will save you from doing headgaskets later on.
-ghost