the shop was bier bros. racing in ofallon or st. peters, right now i have a flowmaster muffler only, im thinking that i can replace the rockers myself, ive done it many times on older motors, just wasnt sure if there was some intricate process on the lt-1. and i agree with you that flowmaster is the biggest pile crap out there for our cars

 

I'm VERY happy with my managaflow catback I do have an issue with it hitting a brace at certain rpm but thats because I'm a vert. I know exactly where it is and just need to get around to fixing it.
Maganaflow - Stainless steel, great sound, great price.