i have a 2008 fa5 si, and i've been running the invidia Q300 with a race header for a couple of months. I love the noticable power increase (thanks flashpro!) but i would really like to turn the decibels up a bit. i figure since i'm already not running a cat, the next logical step is to remove the resonator. i can't find any vids or feedback for the si, but i have found a lot of info from the s2k and mini forums. I'm probably going through with this tomorrow but if anyone has any info...
