I was thinking about installing an offroad x pipe, but wasn't exactly sure what it does. I know it adds more horses, but will your exhaust sound change any too? Also, is it a waste of $$ to put on an off road x pipe w/out putting on new headers as well?

 

There are lots of posts on here about exaust systems. I recommend you review them you'll learn alot about accoustics and power.
The off road x pipe will give you gains in HP Trq. You don't have to change the headers to gain power but... if you do change headers you will gain more power. Same goes for mufflers. Change those and you'll gain more power as well.
As far as accoustics or sound goes any change you make to your exaust will change the sound. Un-catted mid pipe will make your exhaust louder and x pipe has a much different sound than H pipe.
Listen to sound files on exhaust web pages to get an idea of what the sound difference is.

 

cross over explained