Anyone have any picture of the large box under the R6 cut open? The honey comb stuff in the header is the cat, which really makes me believe the large thing under the bike is a muffler. The stock slip on, is pretty much straight through, it's not a muffler, just tunes the sound some.
I like to to tinker too, I'm pretty handy with a welder, and I still went the MJS route.
My post here with pictures. If you really want to do it yourself, he sells a weld on midpipe that eliminates all the honeycomb. All the clamp-on style mid-pipes leave the honey comb in the header.
I went the MJS route just because it was much easier, I was able to just bolt things up, and ride a couple hours later. I bought everything from Mike all at once, header, slip-on (GYTR), smog block offs, K&N, and a PCV, he even loaded the correct map on the PCV so all I did was install things and ride, and that was what I wanted.