[vwipa]

So I’m assuming the Techtonics tuning downpipe bolts onto my stock cat or does it bolt onto my turbo? I’m kinda confused by this since it doesn’t exactly specify on their website and I’m not looking to go catless.

The downpipe does bolt onto the catalytic converter. Those bolts are a bear to get to, FWIW, so be prepared to struggle a bit. A crows-foot wrench helps.

I put a Techtonics 2.5" DP on my Passat after I got a stage 1 APR tune years ago, and my seat-of-the-pants dyno told me it was making more HP

 

[vwipa]

If you want a larger exhaust, a high flow cat is the place to start. The downpipe and full 2.5" setup will add some power, but the HFC will add even more and allow faster spool.

I hope that's the case. My cat has been throwing codes intermittently so I bought an 034 Motorsports cat to replace the stock piece.

 

[vwipa]

What exhaust system do you have? I’m planning on getting an ultra quiet vibrant resonator with my stock cat and no muffler. Do you think this will be too loud? I’m not looking for it to be obnoxious although I still want it to sound aggressive. I’m worried that adding an aftermarket muffler will just make it too quiet

I had a stock exhaust with the exception of the DP. Now I have a full TT exhaust, but the car isn't running yet.

FWIW, I've had good luck with their exhaust systems. They're well-made, fit perfectly and are sporty sounding without droning or being obnoxious.