you have to go WOT to hit full boost. also you might have a slight leak out of the type s. Tighten it until you get a little compressor surge, but don't drive it hard with the surge, then soften it out 'til it goes away. That'll be the tightest setting that won't leak.

Surge sounds like this when you let off the gas. It's a stuttering that sounds like a chugg-chug-chug kinda sound. Don't drive the car hard when you hear this sound 'cause it's not good for the engine, but it'll help you find out that you have the type s tuned too hard.