Don't do it, it rattles like a b*tch. I have had the Invidia Gemini catback and it was awesome by itself, especially sound wise. But the second I put the test pipes on, right below 2k there would be a very loud and distinct rattle that sounds like solid metal hitting solid metal. I've checked the car on a lift and had someone revving it while I was underneath it, and the clearance is fine (somewhat..). Not close enough to hit anything at all, but rather the rattle was coming from the inside of the catback. Other members with this catback have also had issues when paired with HFC.
You can somewhat hear it in this video here, right below 2k rpm when it's decelerating. My phone doesn't capture it much, but it is MUCH louder in person and very annoying.. I ended up buying a new catback for this reason alone
If you don't plan on getting HFC or test pipes though, the sound, price, and looks of this catback is awesome. Very decent gains as well
Oh and as for the tips, here's how far they stick out
