Hmm, you're good at turning the hamster wheel in my head barry.
Most of what I know about anti reversion sleeves or chambers is in regards to non turbo exhausts and design. Do you have any information about how it relates (or if it even differs) to a turbo application?
The simplest design which I would think fairly easy to include in a mani. would be these:
http://www.patentgenius.com/image/6336471-3.html
I'd imagine them directly placed on manifold flange?
Also, on the A/R change I made, the only other variable that I can think which would have made the change have less impact on EGT's would be because the .84 was on the aspec tubo which uses a - according to aspec - more rotary suited (larger I guess) wheel from the GT line, where as the t04-R has the trusty, but very old design, p-trim.
But I'd hope for a greater decrease as well
