Best bet would be to email or call RS-R US offices, they should be able to point you to a local rebuilder if possible, if CA means SoCal you may even be able to take them to the source.
http://www.rs-r.com/contact/
However don't be surprised if they do not offer a rebuild service and would rather sell you a set of replacement dampers. They look a bit like BC/Megan units, so there may be someone willing to rebuild out there given that Feal and Fortune Auto are willing to rebuild theirs (and others) units which are based on the BC/Megan/Godspeed/etc. hardware. Find your local racers, there's likely a little tuning shop that can and will do a rebuild for a reasonable price if they're familiar with the hardware.
http://fealsuspensionstore.com/coilo...es/#coilover-1