Good call using OE two speed fan. I believe the core is similar size on all Classic versions so if it cools a 3.7 Roadster adequately it will more than cool a Plus 4. Ironically this can lead to overheating though. On a couple of 4/4's I'm aware of the overcooling causes themostat to stay closed for longer causing engine temps to rise above normal on motorways until it catches up. I believe a thermostat of lower temp and less hysteresis solves.
