PT Barnum: There's a sucker born every minute!
...Comes with the x pipe as part of the package and if I am not mistaken is sold for around $480 through performancepeddler.com I even read on another forum that there was a coupon code to make it under $400 with shipping. Not sure if it is still valid or not...
It really is personal preference. But you need to do one or the other for sure. I'm running an H pipe on mine. From my experience,this is what I know:
H pipe = more torque = louder = cheaper $
X pipe = more horsepower = quieter = mo money $
Personally I would rather have more torque. Don't go less than 2 1/2" exhaust and run it all the way to the rear valance.
http://www.cardomain.com/ride/2576315
That is closer than the margin of error for any dyno.H pipe: 408 RWHP
X pipe: 415 RWHP
X pipe make more hp and tq then an X pipe across the board-
(well I should say a properly built X pipe- not all are created equal)