If you just want a deeper growl, this is what I did. I added AFE CAI, Magnaflo Tru-X pipe, and ebay "euro" free flow mufflers. The mufflers came with oval square tips. I gained a more responsive SAV. I will soon do Dinan Stage 1 engine and trans soft wear to get some HP gains. Here's what my X sounds like and what the mufflers look like: