You should check out these links . According to LN Engineering, in the past Auto Engineering in Lexington , Ma. has installed their IMS retro fit on a boxster . That's not to say that the other shops aren't capable of doing it, but its nice to know which one has actually performed this procedure .
http://www.porschenet.com/inspect.html
http://www.pcarshops.com/porscheshops/massachusetts/