Dave Deerson (T&Z Auto, South River, NJ-next to E. Brunswick/Old Bridge) is the guy to see. Honest and anal about perfection. Not only does he service Miata's as well as other cars. He builds Miata's for racers from the body shell & frame up. Dave's been servicing my street Miata's, my race Miata's and my Corvettes for at least 20 years.
You won't find any one better then Dave.
Only draw back is because he's so anal about perfection he does not have anyone working with him. He's a one man band. If you call you may not reach him the 1st time but keep trying.
It will be worth it to you.