I hear Larry Garcia at NSX Modified is the guy. He's in Irvine I believe.
Here are the directions I received from Alex to get to one of the meetings. Remember to join the NSXCA if you havent already.
TEAM NSX, Inc.
17222 Gothard Ave., Unit E
Huntington Beach, CA 92647
Directions: Get yourself on the 405, exit on Beach Blvd. Go South (towards the beach). Turn right on Warner, pass railroad tracks, next light is Gothard. Make a left on Gothard. Look for the complex that
has Frank's Auto Body at the corner, TEAM NSX is at the very end of this complex on the left hand side.