If you don't plan on any kind of performance HP upgrade you should just cut the muffler and cat off for $50 instead of spending 3 to 7 hundred on exhaust for no reason. If you can't do the cat, muffler should be good enough. If you don't plan on edge, van aken, or any of the other boxes or programmers that is what I would do. That is what I did, your stock exhaust is already 3.5. I am running a 3.5in staight pipe no muff no cat with 2 MPG gain. JMO.