well theres a store here locally that sells all that stuff. its the place that the company i work for uses for all tis regualtors for the air compressors at work. i guess any place that sells air compressor hardware would have these. just be sure to get a good precise one, not a cheap one that could cause serious problems controlling the boost pressure! i purchased the regulator, the guage, mounting tab, lock ring, & barb fittings for just under $40. you may be able to get it even cheaper online somewhere, but i wanted a good precision regulator that could control good at low boost levels since the regulator would be controlling boost pressure as low as 1 psi & i didnt want to take any chances messing with my fuel presure! the unit i purchased is precise from 0 to 30 psi of air. the guage i got has 1 psi graduations so i could guage the amount of boost closely. im assuming everyone knows how to figure the amount of boost going through the regulator & how to figure the desired ratio!
-justin