I built my system myself. I purchased the mufflers from Geno (ONEBADMK8) and I parted the rest of the system together. It is all up to you what you do. Just wanted to give you options. BUT, one thing that I recommend is that you have the exhaust flanged at least in the front so that you can drop the exhaust without having to cut it out when you have to do anything else to the car underneath. I did not have that done, and would have had to drop the whole exhaust from after the cats to the back if I would have needed to even put in a new fuel pump on my car........