Has anybody put these on their TT and noticed a real difference ? power or sound or both. The ones for my 996 CAB certainly were worth it

 

The turbo is a different beast all together. The idea is to get the air going faster to the turbos. This in turn allows the turbos to spool faster and make power sooner. The factory headers are a good setup and gains are small until you start trying to push BIG power. The typical response we see from ported/coated and triangle design is apx 250RPM faster spool. Very little HP increase to speak of.