I'd say it's in the carb/enclosure combo. The hats are a much better way to go, especially at higher boost, but require more carb mods. That enclosure should work at that boost level but I am totally unfamiliar with the carb mods needed with an enclosure. I know mine did a similar thing before being modded correctly. I'd recommend CSU carbs or SD Concept Engineering for the carb mods.
http://www.sd-concepts.com/
Jody