so right now my 2001 a4 1.8t has a 2.5 inch straight pipe from the cat back. everything else on the car is pretty much stock. when i let it scream, it sounds awesome. however, at low rpms, it sounds like a worn out camry. what kind of resonator can i weld in that will clean up my idle and low rpm sound, but keep the high rpms sounding mean and raspy? im open to all suggestions.

also- i have a 50 dollar gift card to ecs tuning, any ideas on how i should spend it?

 

Have you considered an aftermarket high-flow cat or test pipe in place of your cat? That will allow it to sound deeper/throatier/meaner. Then you can put in a resonator as well. My car runs a Magnaflow resonator, not sure which model but it's round and is 2.5" in/2.5" out.

 

was thinking about this

Audi B5 A4 Quattro 1.8T > Exhaust > Test Pipe > ES#1844140 B5 1.8T Race/Cat Delete Pipe Kit - ATP-VVW-138

is this a simple bolt in and out? it looks pretty tight underneath the car. how easily can i avoid a check engine light?

 

That will fit directly. This is what I use to get rid of CEL due to a high-flow cat:
O2 Sensor Spacer, For Bosch Style Sensors - 034 MOTORSPORT

 

I run a Vibrant 12" perf-core resonator along with a Magnaflow 14816 and custom cat-back piping and love it. The resonator makes the tone a lot deeper than the OEM resonator. I have a 30v but the 1.8T seems to have similar results with exhaust mods.

 

I use the same spacer on my TP and have yet to see a CEL. To be fair though, it's only been installed for a day lol