Hello Wonton, nice to see another monty guy in SM. Not a Mitsubishi specialist but George at Santa Monica Brake (911 Santa Monica Bl) runs a well respected local shop. I've also heard good things about C&A in Van Nuys if you want a dedicated Mitsubishi shop. Good luck!
Another vote for Miyaki Motorsports in South El Monte. Owner had a Gen 2.5, now has a Gen 3.5. Lots of Mitsu and Yota guys go here.
2623 Tyler Ave, El Monte, CA 91733
(626) 453-8991