So Cal Nissan/Infiniti Performance Shops?

Have a 2004 350Z and 2005 G35 Coupe ready to start doing upgrades to. Looking to see if anyone has worked with any shops in the So. Cal area (Orange County preferably) and what their experience was like.
First upgrades are likely going to be suspension, but don't just want a spring kit, want someone who knows how the different pieces compliment each other.

Any info would be appreciated. (And yes, Stillen is right down the street, looking for others)