If your looking for a race shop in NJ you can't go wrong with GS Autowerks in Oxford. Not a Cobra specific shop but also not a high pressure operation with lots of BS thrown at you.
If you are tired of dealing with the race shop "knowitalls" you will really be impressed with these two guys,
owner Nick Guarriello and right hand man Rob Scagnelli.
Check out their shop at,
http://www.gsautoworks.biz/gs_002.htm