Mr Literal here.CTS catted down pipe.
other than MA having a legal tint level that is almost pointless, modifying cars here isn't overly restrictive that I'm aware of. been modifying cars for years with no big issues. only when it comes time for inspections, which is inconvenient but you can work around it swapping parts, etc.
Why not just make a stg 2 tune for inspection w rear o2 on? Flash it and drive until ready? Or is it impossible cuz it will/must throw a code? What seems to be the issue w cobb specifically?
My wrx has rear o2 turned off and all monitors are ready except egr (which is unplugged and tuned for). I have a map w egr on (after i plug) for obd readiness emissions in my state when time comes, which is why it makes me think why you couldnt do the same for vw in regards to o2.