That's really hard to say with the t6lcbc builds out. I would normally say about 700b, because that's about half your stats, but nowadays you see 6.2mcs bc's that are only 1.5T.
What substance was being used when the developers came up with the idea of PIMD and if this particular substance was from the earth do you feel it should be legal
Going by half your stats you should probably be a little over 790b to be considered op, although hire price is really determined by what the person is willing to spend to keep a particular tutor. Usually over 100kcs it goes by half your stats to be considered overpriced; until you reach lcbc in which case op is considered to be over 2T. Again that all depends on the person hiring, that's just a rough estimate and market can change at any time.
You upgrade by getting enough money and then going to [Dorms] and upgrading your dormmates. It'll increase your stats.