Jtune in Wilmington DE:
J-Tune Performance » Nissan and Infiniti Performance Specialists. Dyno Tuning. Everything For Your Motorsport Needs.
R/T Tuning in Landsdale PA:
R/T Tuning – Dyno Tuning & Engine Performance Specialists
I don't have any experience with either shop and they aren't exactly located in South Jersey either but they are both sponsors here and seem to have a good reputation.