i put my mac o/r H in about a month ago... and since the flanges are just a hair wider where it meets the cat-back compared to the stock h pipe, my mac cat back has a nasty rattle when i turn the wheel even the slightest bit to the right ( chassis twist from the convertable i think) after countless hours of fixing this it always comes back. it either hits the frame near the muffler, the frame above the axle, or the upper control arm... i think mac made their cross-over pipe a little too wide and if it was shorter it would help solve both of our problems, just try loosening everything up and you should be able to pull it down enough then tighten it while still pulling down on it and it should tighten up in that position, as for me there is just too much give in the rubber isolators for the tight squeeze now, this sucks. As for wedging, it probably wont work unless it's somehow attached to the pipe or frame, i wedged various things to fix my problem and even the tightest fit usually only lasted no more than a day for me