Paint Body Shop
 

Anyone who could recommend a paint body shop within So. Cal. that could match the whiteout (37J) paint ?

find one that specializes in Subaru's it is a Subaru color

The people at European motor car works in Santa Ana are great.

What I've suggested in the past is find a high end dealership (Ferrari, Rolls Royce, etc.). Because of their small volume it's likely they don't have their own body shop. That doesn't change the fact that often they need body work done and they can tell you who they use which will probably be the best body shop in the area. Don't be surprised if it's off a back alley somewhere. It's not the shop that indicates the quality of work but rather the man doing the work.