Which place is the best to get O2 sensors for? Pacific BMW?

Also, I need to replace my RTAB's .... I need to do it ASAP. I have SCCA national tour coming up next weekend and prosolo after that. Thus, I need something now, any suggestions or am I stuck with stock RTAB's?

O2 sensors are pretty cheap at "Eurasian" in Temecula, CA.
Also, Nick Alexander BMW has very good prices with a CCA card.