Im pretty darn sure ive got the 3 inch.. i have the fattest pipe under my car... its huge.. But ive got a long road ahead of me with my car. I need a new alternator, i need to change my oil out for 10w50 as advised by my mechanic and i need a new induction boot. The LTs and duel cats will wait, Ill just go with a singlehigh flow cat for the time being.