exhaust..
As a side note: I removed my dampeners and did the heater hose mod (push on 3/4" around the top coil) and mine make a ton of noise when going over bumps. So I'll be cutting the dampeners down and throwing that back in. Not sure why most others don't have this problem, but I sure did. I even put hose on the bottom coil too and didn't help
You COULD always get custom springs that are like .75" drop. I want to say I've read that the 1" drop springs still work well with headers/duals. Also I've seen some pics of people's duals that are VERY tight against the body, so it could've just been a lackluster install job that some smaller hangers could help with. 
