+1You can also try Integrated Performance in Hawthorne.
Their history and background go back to Brainstorm in Culver city.
Alex is fair and you can bring in your own parts/supplies/gaskets etc etc. (which I did with a Rosenthal kit)
He is currently prepping other customers miatas for track duty, as well as regular maintenance stuff.
3820 W El Segundo blvd unit A
Hawthorne Ca, 90250