Is there any such thing as a pardon for a DUI charge long after all requirements have been met ?
Yep. All you have to do is contact your state governor and convince him that he should pardon you for your crime(s).
However, if you mean 'expungement'... the answer is no. For some strange reason, NJ only allows expungement in "case of arrests for loitering or prowling and DNA records of persons whose convictions are dismissed or reversed, recorded are expunged as a matter of law. No petition is required. RSA 644:6, 651-C:5."