W/ a header, I'd a stealth muffler to the order too. It bolt's right up to the fwerk's flex pipe. & Yes get the 2.5'' flex to go w/ the header. Your going to love the ceramic coated header. Add a tune w/ the rear o2 senser & egr delete. Don't get the regular fuel tune option= it's worth the 2-4.00 per tank to for the performance. I ordered the reg, fuel tune & have yet to use it. For some pix, checkout my pix album's.
Interduce Mr. Torsen to the mix
D23 crew- D-Tech- Sedan Revolution= #131