10 lbs, 10 PSI, same thing... pounds per square inch. With 10 PSI, at least you would probably never have to upgrade it anymore, unless JR actuqally came out with an intercooler sometime in the near future (very doubtful). 40K +25K isn't too bad... What's the asking price? I'd assume it would be no more than say $3500.00 Anything more then that and I'd start questioning the value of it. Also, before you buy it, see if you can have a compression and leakdown test done on it, as well as taking just the blower off and lookiing at the blades inside... do they move freely? Are they still coated with their enamel, or are parts of it chipping away? As long as all the enamel is there and you can spin the blower by hand without any friction, then it should be fine.
