i highly doubt a diverter valve would have dropped off since it sits on the top of your engine and is connected by hoses that are about the size of your pinky finger. Like john said it sounds like your intercooler piping. Check all the piping and follow it all the way in and out of your intercooler. Unless you have an aftermarker FMIC your intercooler will be right in front of your passenger side tire in the fender.

As far as upgrading i say go for it you can never have enough power. If you want a quality setup that will keep your car super reliable check out APR Tuning. I have the 1.8t with their Stage 3+ setup putting 360 horse on the ground with pump gas. I will admit they are not the cheapest but are one of the best for vw/audi/porsche and the customer support is absolutly top notch.


is your check engine light on?



this is what your diverter looks like its about 2 inches tall by about 3 inches wide.... i dont think that would have made the loud bang your wife said she heard.