im debating on two kits myself i like the whipple and i like the new tvs kit from eaton. the tvs kit depending on your tune can give you 500-700 on the stock block and its under 1 year/12000 mile warranty where the whipple is not there both around 6 grand the tvs whines alot louder than any other kit out there the whipple is second and the kenne bell you can barely hear and all claim the 500-700 but no warranty from the other 2 plus the eaton kit is from roush so it still maintains your factory warranty if your still on one and they supply a tune and duel fuel pumps for an extra 1000 dollars... but if you want to go turbo i like this hellion kit from Hellion Power Systems - The Leader in High Quality Mustang Turbo Kits, Complete Twin Turbo Systems, and All of Your Mustang Performance Needs. they send you every nut and bolt and every single thing you need for your kit so you never have to go to the hardware store its base price is 5k with the turbonetics 62mm turbo but u can ugrade the kit to a t-76 ball bearing with turbo heat sheild and blow off valve for an extra 1200 bucks making the kit around 6200 turbos are much more efficent but take longer to spool up hope all this info helps