get a copy of Porscheforus sold by the NOrthern New Jersey Porsche Club. There are several shops advertising there. One popular sponsor is Power Tech in Rockaway. I think their hourly rate is $90 an hour.
www.pwr-tech.com
there is also
PROTOSPORT
17 EAST GARDEN PLACE, POMPTON PLAINS, NJ
(973) 839-5353