Originally Posted by MaDMaXX

Those numbers will be about right.

But be careful what you're looking at, numbers for parts do not stack. Everything compared to baseline, so basically, the exhaust, the y-back section, will net you anything from 10-15 HP for most good y-back systems.

Extra gains can be made by freeing up the cat sections, which is the other numbers being shown, but remember, that's not so specific as the stock vs just the y-back comparison.

If you go test pipes, just make sure you go resonated test pipes, otherwise you'll hit massive rasp/rice as you put it. The FI resonated pipes are show in that chart, the other options are the Motordyne ART pipes (resonated test pipes).
I don't know about the FI pipes, but i do know the ART pipes help correct for lost power and torque low down that test pipes usually cause.

Depending on what you prefer, so this is personal to me, if you want cats in the mix (they're better further downstream) then i know the Motordyne system has a modular (v-band) HFC available to fit shortly after the y-pipe and first resonator. I do not know if the same is available from FI.

I've heard both on many many vids now, and both sound great, but if i had to chose based on vid sound alone, my choice is the MD, it just has a certain, "fruityness" to the sound, like it was specifically designed to be this way, it's deep and no rasp, so that sold it for me.