You might.... see a slight increase in hp, but not enough to bothering swapping from ah H-pipe. If you still have a y-pipe, then yes go with a X-pipe if you can. Your exhaust tone would stay the same if you had an H-pipe. The only thing that will really change that is different mufflers or if you get ALOT of air moving through your exhaust.
Right now I got my stock Y-pipe and duals from Flowmasters connected to the Y-pipe. My problem is that since I'm lowered, my driveshaft hits the exhaust pipe. I know a H or a X pipe will help me and my problem.
still though i doubt you get any real gains, im sure a little but you will move your tq up a tad... its a step on the road of modifications though if you do plan to go into the motor you will eventually need it.
Yeah I know it wont give me much now, but I do plan to go into my motor and get more performance. Right now I'm just doing it due to the scraping of the driveshaft and exhaust pipe when I got 2 or more in the car (usually only my girl, me and our 75lbs dog).
My dream is to drop a V8 in it, so I might get a crate engine in a few years from now. So I mod my car with that in mind.
No cats sounds like ass on a stock V6 but a built engine with a cam is entirely different. Robs car as well as mine sound pretty damn good. I am always having people come up to me and say they cant believe it is a V6. At idle it sounds like a 5.0 but when the RPM's go up it is entirely different. It has a unique sound all of its own. If I was to say what it sounds like. I would say it sounds more like a heavily modded V6 supra or 300Z in the 2000 to 3000 rpm range. Here is a sound clip from Team Fords SCT Tuning Day. Krazy Pony took these while they were dyno tuning my car. The guy slipping on the dyno wheel is Mike Troyer who owns a Ford Truck Customizing shop in Maryland I believe. HAHHAAHAHA