i,d say start with atleast 8 to 1 comp. any lower and the engine will be a turd. higher than 9.5 and you will be boost limited by fuel very quickly. i presently have my engine around 8.25 and have run the boost safely to 12 with 91 octane. also using a intercooler. i also run 1 turbo. it simplifies the install. some will say 2 turbos spool faster, but i have found that if set up correct 1 turbo spools plenty fast. especially on our relatively small cube motors. tom
