Some questions after HFC install

NRGz

After being able to get the stock cats out and the FI RHFCs on, i have some 'issues' that I have came around, especially in reverse!
09 7at

I did have to unbolt the Y pipe- and eventually had to rebolt the whole catback from the cats to the back mufflers so everything will sit norm again.

The rattles like to come around randomly and goes away when stopped. Rattles for sure in reverse. Cruising is as quiet as stock cats.

Vibrations/rattles! I have found the first suspect which is where the midpipe sits. After a quick wrap and wedge, the midpipe rattle that was hitting the brace was out.
License plate rattle was fixed with a quick wedge of rubber.

This last vibration is happening to what I feel like is under me- at the cats. I dont see anything touching. The brace that held the stock cats was removed due to not being able to fit with the o2 bung in the way.
BUT one problem i had is where the 'demon bolts' are, two top bolts. After many cuts and bruises i managed to get the nut on the other side. But now all i can do is turn the bolt tight enough to when the nut on the other side starts turning with.. which is tight... but not as i want them to be. Ha.
Squirt bottle test shows no leak at the demon bolts, both idle and slight rev in park. Everything else to the axled is goodtogo.
No check engine.


When going from a stop, it feels hard. Which is around 1.5-4k when the exhaust sounds the loudest before smoothing out to a mellow vq rumble.






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