I was in Lafayette ,Indiana in the summer (I know its not the east coast but I thought it might help out). While was there i had never seen so many american cars on the streets. There were some imports but not as many as in Cali. Well point is that there was a lot of posers and not many serious tuners. My buddy recently moved out there and has a VR4 Galant thats well built(beats a Z06 on the streets). Only two cars gave him a good chase. A wrx wich beat him and a turbo Civic wich kept up until mid third gear. We stopped and talked to them about local shops (there were none worth naming according to them) and they said they practically had to go to really far (like chicago,IL) or online to get the good stuff. Funniest thing I seen there was a civic hatch with a wrx front end.
Hope this helped.