I just reverted back to the original stock midpipe. Even with 12" Vibrant Resonators, my Lethal Perf. offroad x-pipes were way too raspy beyond 3k rpms. The sound was too loud for me to enjoy the gains.
I'm also very interested in this XFlo muffler, curious if they inhibit power. Raided youtube and didn't find any 3.7 videos. I'm going to call Lethal Performance if they have ever recommended these.