[quote name=
So, what criteria should I be looking at for a used 7 for me to be able to register / use it in MA?[/quote]
Buy one that is already registered in MA, but the truth is unless they have modified the law from 2012/2013 when I was dealing with it even this may not work.
When they put this new law into effect in 4/2011 there was a 1 year grandfather period for "replica" owners to change their title/registration to comply and be forever exempt, the rub is they didn't tell anyone. After that there is no exemption, that is, it is retroactive applied to all replica cars even if you have owned it forever. There is also no "age out" for replicas as there is for passenger cars which don't have to pass emissions after 15 years. There was talk of correcting these issues in the law, but I don't know as I have not followed it since 4/13 when I was done, however the lawmakers are not known for their speed.
The biggest problem is lack of knowledge by officials administering the rules (don't believe what you are told unless you can verify it) and much rumor amongst car enthusiasts about the old easy ways around -there are not any in this RMV computer run system. I have heard of a case where a title/registration was issued incorrectly - to the advantage of the owner, but this was only a mistake by the clerk (and the law was new). I urge you do your research and look carefully at the laws that apply. I can provide links to most.