well I have not used them yet but im going to Wait4uperformance.com Ive talked to them on the phone and they seam pretty knowlageable oh buy the way they only cost 360.00 out the door for a harness rebuild and tune. where as nelson is 650.00 for a stand alone and 225.00 or 250.00 for a tune. wait 4u is life time tuning also so if u up grade you just send them the pcm and they retune it all you spend is shipping. I did not see where your located but if your in texas texas speed is jam up on there tuning and performance mods. A guy in midland texas does lots of conversions I believe his shop is cars and parts from mars I talked to him and he uses anoter place out of sa antonio but i don't remember what its called but he told me Nelsons are good but they are for someone with deep pockets and wanting bragging rights