I'm about to start Modding my a 4 b7 for the summer. I'm thinkin about getting Apr Ecu flash and 034 motorsport high flow cat. my first question if I upgrade my cat would I require to get a spacer for the o2 sensor if I get the Apr stage two flash?

 

Nope... Stage 2 eliminates the cel. The real question is "Is it posible to run a test pipe without any kind of programming and be able to avoid getting a CEL"???

 

I have the 034 HFC, and the spacer didn't stop the CEL anyway, so I got the stage 2 programming.

 

good to know. save me some money for the ecu tunning XD. and also do i need to get new gasket and bolts?