I started building my own exhaust as I mentioned in my other thread (acquiring my 2nd ISF), I work two jobs so finding time is nearly impossible, averaging 12-14 hours/day between the two. Anyways I started with the axleback section because it is the easiest.
I did run out of time tonight but I got majority of it done and I will be revisiting it later! I rushed alot of the welding (autogenous, and some filthy big gaps w/ 1/16" rod) because I was impatient and I couldnt align the exits directly through the quad stacks nicely. Gets fairly warm under there as my hand can attest too after the drive home.
I made the axleback section from 3" piping from Treadstone performance 304SS, I believe it to be .049 to .065 wall thickness based on welding amperage. It also looks way more elaborate than it needs to be (didn't have time to use hangers at the rear of the mufflers so the midpipe ones had to do, welded some tabs and used poly hangers and it doesnt rattle at all!!) I used ALOT of my scraps and pie pieces from other projects.