Blower for modular engine

[84_GT350]

Ok....I'm really new to modular engines and need some advice. I'll soon be buying either a 99-00 GT or a later model (97-00) Cobra and I'm planning for a blower. I've narrowed my choices down to ATI Procharger and Kenne Bell. Anyone have insight as to which would be better? I'm looking for some pretty serious power (at least 400rwhp) since this will basically be my only mod. The complication of the ATI kits doesn't matter since I live right down the street and could have them install it. I know the Kenne Bell adds a lot more low end, but I would like around 12lbs of boost and I can't run that with a Kenne Bell on a stock engine without the detonation worries. I know all the ins and outs of the 5.0L engines but I'm pretty clueless about 4.6Ls.