I'm running 275's, TST PM3, and a VanAaken box (which is almost identical to the Edge EZ). And it all works great. I've been running that setup for at least 100k miles. I use the PM3 with the remote so that I can preset the EGT limit which is an EXCELLENT TOWING setup.
I notice you are in Firestone, Colorado. If you want, we can get together and you can take it for a spin. Send me a PM. Although, my truck is a 5spd and I don't have the 4" exhaust, BHAF, and the modified turbo.