Don't know about Cyberstorms as I've never owned one, but I have owned plenty of A1200 DCE / Phase5 hardware.
I have no idea were this, scsi won't work if you overclock it, myth / urban legand came from.
My BlizzardPPC was overclocked to 280Mhz by uping the bus speed to 70Mhz (x4 multiplier) and didn't affect scsi. That was on an unfixed 1D4 mobo as well.
My current DCE1260 is overclocked to 66Mhz and has a phase5 SCSI card on it. It works just fine.
My previous Phase5-1260 which I overclocked in 1997 to 64Mhz is still going to this day with SCSI at my friends house.