I went with the dcai on my na. I also deleted all 4 cats. That is the real exhaust mod, cat-backs dont do much. I also got the evo sport pully kit and deleted my air conditioning, magnecor kv 85's, ngk irridium ix's, updated fuel filter, wideband and soon an inmotion tune. Ive timed 0-60's around 5 seconds flat with sub 70 degree air temparature.