I have TTI headers & 3" X-pipe on my Dart with a conventional driveshaft loop. I had to dent the tubes near the X to clear. I'm sure it didn't hurt flow. I had a little back & forth adjustability available because the loop was already there and I was adding the X-pipe & exhaust. I think I had to do the same with my Aspen wagon, so it appears that a little denting may be necessary in most applications.