I ordered a Calmini kit myself some time back and found out very quickly that it is far from a "direct w/o hassle" bolt on application. There was one section on the OEM exhaust that was press fit so if you have a good dremel or very strong arms to wrestle it off you should have no problem from that point on. There is a recurring problem w/ their mufflers. The pipe that enter/exits the muffler can is press fit and not welded very well. After less than a year, that press fit let loose causing the pipe to rotate w/in the can. There are some other posts noting this problem w/ other owners. My best advice would be to bolt on a Flowmaster 40 series in place of your OEM muffler using the stock piping throughout. If you however wish to go w/ a larger pipe diameter, I would encourage you to look into Gibson as an option, 4x4parts.com sell them pretty regularly. Good luck w/ your choice. If I can be of any help let me know.