Just got it on this weekend. The cat bolts were a pain, the AIV tube I could not get loose from the stock manifold. (I just used the plug supplied and a rubber plug for the little black box) I added a brand new O2 sensor as well. Folks if you are thinking about getting one, DO IT. I can feel a difference in how the car runs. Esp. above 4,000rpm. What's really cool is I can totally hear the air getting sucked in through my Stillen Pop Charger. It was not this loud before. (engine can breath better) Two big thumbs up for Hotshot!!!