So, I just took a look at the headers, and I don't know how I'm going to be able to dent these while they're still in the car. I have some flat ended punches and I can barely fit them around there. Even with a rag on the other side, I'm worried about puncturing a tube or something as I gave them some slight hits and knicked the surface of the tubing.

As for the exhaust, the tips seem to go from the mufflers to the back of the car. So any modification will require some welding... Speaking of which, I just got a cheap flux core MIG welder for Christmas. However, I won't tackle that as my first project.

Looking at the underside, I have some room between the leaf spring and the gas tank. My exhaust is actually a lot closer to my leaf springs than it is to my tank. But if I go to the resonator route, there's plenty of space past the gas tank to mount them.