I have a 1.8T with the APR stage 1 flash. I've been reading about exhausts and test pipes. So could you just replace the cat w/ a test pipe and just swap out the mufflers w/ Magnaflows? Is there something else in the OEM piping that is restrictive? Is it even worth doing this? I'm looking to upgrade to APR 1+ later on. I just want something that sounds a bit throatier at idle, and any gain performance would be a plus.

aloha, Derrick

go custom....as far as doing what your talking about it doesn't sound very efficient. Being that the test pipe is probably 3 inches then it would go in to the stock pipes w/magnaflows. Test pipe is worth it. better spool up and sound!!!

Well you will get some louder exhaust, but that's about it.
The whole stock pipes are really thin, so you gonna have 3" (or 2.5") TestPipe, then like 2" (if not less, i dont know for sure the diameter of a stock pipe), resonators (even though they are not that restrictive) and than again 2.25" Mufflers.
To see the full potential of a TP you need to have a full exhaust.

just install a 3" test pipe, a 3" down pipe and remove the rest of the exhaust. loud and no restriction, you win!

It's actually my wife's car. I was just looking for something not too aggressive or with any drone. It's gonna be installed on a Cabrio (if that matters). So I should go with a 3" test pipe (replaces cat), 3" Y-pipe or 3"to 2.5" Y-pipe, 3" or 2.5" tubes going into mufflers. Where are/is the resonator located on the stock exhaust. I figure leaving them/it on will tone down the drone. Her car will only have the stage 1+/ K04 (maybe way in the future), so which size exhaust will work best.

aloha, Derrick