Mass is supposed to have CA emissions, but they are much less strict. As long as you do not make it louder and keep the cat, they do not care about most performance mods.

However, plugging into OBD2 port can be a liability! In the last year, they started tagging "tuner cars" with reflashed ECUs and sending them to a higher level inspection (these are ran by state, as opposed to local repair shops)! I wonder what it would do if your VX gives them mid 00's GM readiness codes?

In Mass, they stop checking OBD2 after 15 years, so I have 3 more years of worrying about it