I wouldnt bother with the thermal fo rhte effort requried. BR exhausts are well proven. RRE sells the N1s. VSR is good as well. You really cant go wrong with any of them. The differences between them are slight. I do prefer exhausts that use the Dynomax Ultraflow (SS or Welded), which some if not all of the BR models use. Actually I think it was VSR that they actually use now. But its been a while since I last looked into BR exhaust, about a year now. The BR 2.5 uses the dynomax. The VSRs use magnaflow, which isnt bad either. Same type of muffler as the dynomax. The bends all look good, etc.
Exhaust systems dont vary much by brand when it comes to dSMs. ITs not as critical a choice as it is with NT cars where you are worried about losing toruqe, etc. It just has to flow well enough for the power you are making. Look for 3", straight through muffler, mandrel bends, and no neck downs anywhere. You wont see the power differences between the different brands like you will on NT cars.
