Will replacing the downpipe affect my emissions? Is it only if I replace the catalytic converter? Keeping the stock cat should be okay right?

 

visual it will pass, emissions it might not... turbo will have a slightly different responce to throttle

 

i would install stock downpipe and cat back on, you can leave the catback if you wanna pass.

 

It really depends on what your inspection station looks for.. since the car is AWD, some states don't require a dyno (rolling road) sniffer check. In that case, its likely it would pass without problem.. To be honest with you, it probably would pass with quite a few modifications since we're really not making the car run dirtier (if you leave the catalytic converter on, or get a high performance one). Its tough because some states require only an OBD-II check.. some have a smog check, some have both, some have safety only for the first few years.. etc.