Chris,, mine are 2.25" they are mandrel bent (I dont think they have to be) and are adjustable from 30" to 38". I have them on my 2.5" tailpipes. I dont hear a real big difference with the range of adjustments only slightly. I run them now at 38" and it tames the drone perfectly. These were designed, made and sold by a local muffler shop and they use them on all the mid pipes when they install performance exhaust on all the modern muscle cars (ford, chev, and Mopar.) I dont think they have to be curved either. Good luck and let us know how they work out. Cheers. Larry
