"H-pipe," X-pipe," or no pipe?

You say that like a it's a bad thing. If it sounds that smooth, then I'm sold!

I'm actually planning on going the X-pipe route, but I don't know if I want to get the Summit brand or the Pypes brand to go along with my Doug's headers. I kinda decided on the Summit brand welded Flowmaster knock-off mufflers. Or, I might use the Magnaflows I have but I don't like how they sound.

There's also a local muffler guy that makes them that comes to the Long Beach (CA) High Performance Swap Meet often who I plan to check out soon since my engine will be ready by next week.

I used the Summit X pipe on the stock 5.2 with the Hedman shorty headers and a 2.5" mandrel bent custom exhaust with the Summit dual exhaust kit with the turbo mufflers...I don't think it sounds like a Mustang at all. It sounds like a smooth running stock small block V8 through a generic exhaust system with a crossover. Truthfully speaking, I'm pleased with the way it sounds.