Depends on what you have to tune. With a standalone system like hondata/neptune/etc and a good tuner, I've seen 13:1 run. With no ECU mods, I've seen around 11.5:1 run on premium. On regular, I wouldn't go above 9.5:1. If you want to bump the compression, you're at least gonna have to run premium. To get the most potential out of the B18A all motor, you're going to need a VTEC head.