Are you building a package with Mike that will include maps with your exhuasts? HUGE!
Yep. Pricing for the map is up to him, but if it's anywhere close to what I expect for power, it should be worth the cost.

appear to set the standard by which those of the other current manufacturers are judged.
Nope, not by a long shot. I can weld, but there are guys out there that put me to shame.

I'm curious, why does your RT-XB1 use two mufflers, instead of one? Have you done any dyno testing on a single-muffler system? Would you consider building one for me?
Design choice to make it fit within the stock mounting points, guess I just got lucky with the power gain. I have built a single oval body muffler, its the RT-XB-3, I also did my version of the magnaflow exhaust, essentially they're the same thing other than materials. The magnaflow is 409/436 ss and mine is all 304 ss. Even though it's more time consuming to build them, I actually prefer to build the RT-XB-1 over the other XB systems. Dunno why, but there it is. Might just be the way it sounds or looks. Nah, it's the power.

Have I done a single straight through exhaust for the XB's? No. Can I? Sure, just haven't done one yet. I have no idea how it would perform though. I'd expect similar results to a jardine at worst. It will be a while before I build one if I do, I'm averaging at least a 4-5 week delay on building stuff, guys keep ordering so I never seem to get caught up. Maybe I should stop posting pics? I know it gets at least one other builder's panties in a bunch when I do.