ORIGINAL: 46u
Are you running 30% with the 4mm shim set up? If so have you pulled the head and check out the top of the piston? I will be starting next year with a new Hyper 8.5 with a new STS D21T MKII. I have one STS D21B with well over 5 gallons on it still running fine.
no, not yet. haven't needed to remove any shims, but probably will one day (don't ask me when)
EDIT: I might mess around with it when I mod it, but don't know when thats gona be, maybe when I figure out what I'm doing