Correct me if I'm wrong, but I always thought the oil cooler only gets oil when the oil temp gets hot enough to open the internal thermostat in the oil cooler housing (similar to the radiator). If this is true, there will be times that there will be no oil flowing to the cooler and therefore, the bypass filter will be useless. Also, regarding tapping into the turbo feed line, when you "T" into something, it becomes a parallel circuit, so theoretically you get the same flow rate, so it should have a negligible effect on flow to the turbo. I hope I'm making sense, its been a while since I looked at my fluid dynamics books.
