I've done business with George at Short Circuit a few times since NICOclub was founded over a decade ago, and George has been with us the whole time.
He and his team are magicians with factory audio systems, and they're a Clarion Authorized Repair facility (Nissan uses Clarion head units in most of their vehicles). They're also adept with Bose units, which appear in many Infiniti cars.
Check out this article from George and his team:
http://www.nicoclub.com/shortcircuit
Enjoy!