Hello all, I'm potentially moving out to Denver with my job and have a few questions about registering a car out there. I have a 2009 335i e90 and I am starting to do research on exhaust mods. Not looking to get rid of the stock DPs, but could you run the HPF system with stock cat DPs and still pass emissions out there? If not what would be the options to keep it legal on the street?
Here in NC I have a guy, so I don't worry about questions like this.