Thanks for the input. After looking at it, and reading the yotatech site, here's my plan. Plug off the crossover entrance to the driver side header. Cut the crossover pipe and welld a 90 into it, and graft it into the existing down pipe. That's the minimal amount of work and sounds like 1/2 decent improvement in flow. It still allows the passenger side rear valve to see more exhaust gasses than ideal, but I think the cylinder that gets the most abuse is the driver side rear.