Mine was hitting the rear axle(crossbeam) or whatever you call it. I saw an article in Sport Compact car long ago about them having the same problem with their project Subaru WRX. Well, they used long zip ties and put them around some of the hangers to pull them up a bit....it worked great for me! Just wrap a zip tie around the hanger, push up on the muffler/exhaust and tighten the zip tie as tight as you can.

http://www.cardomain.com/ride/3130861