I would have thought that a larger air cooled radiator would have been the go. The problem, like you said, with the inline cooler is that altough it is simple, you are going to have trouble with heat sink... I am tempted to bypass the radiator all together and go air cooled with something like the RX7 cooler. These are huge and there are plenty around. The other benefit with this system is that the radiator get back to what it does best and just cool the coolant. Constant oil temps shouldnt be to much of an issue due to the thermostat in the oil system. But having not done this conversion I cant offer any real data...

