Hello pete
If you have a gain control on your subwoofer for LFE, I would set the LFE to 0db, but I believe for Sony this means reference level output - really loud, so I would start by setting your sub's LFE control at a very low level and then work your way up.
I don't think those frequency options are to boost the signal, but rather have to do with frequency cut offs, though it is a bit confusing. Did you get a manual with your Sony? If so, let us know what these settings are supposed to do. I think the M22s drop off at 80 Hz, and the x-over from the mid woofers to the tweeter is at 2,700-3,000 Hz (2.7 - 3.0 KHz).
WRX, sweet ride! Manual transmission, I hope.
