fstr n u

Essentially both the X-Pipe and H-Pipe add slight power to a stock engine....the x-pipe adding trace amounts more than an h-pipe. H-pipe sounds more mellow...x-pipe sounding better at higher rpms.

Liquid Smoke

i would say in your situation, the S5 is better. like mentioned it can pretty much get close to RS5 power, stage 2 isn't too far off an upgrade either and get you a bit more power there. and if you are just DD and some fun driving, nothing crazy you dont even need the full RS5 power and performance.

the S5 should be more practical and comfortable, better mpg i assume, easier/cheaper maintenance, and not only is msrp is ~$20k more, but with the current market the RS5 has a big markup on the price as well so take that into account if shopping new. unless it wouldn't have an effect on your wallet, financially/practically speaking the S5 makes much more sense.

SpeedyG

I had the X-pipe installed on my S4 and it was great until I went catless, then, Holy Cow!!!! Way too loud for my taste. If you are going to tune and plan on going catless, wait on the x-pipe until you do that first. I ended up removing the X-pipe and having a custom exhaust built.