no reason not to go with the specified coolant so far. I used to own a Cooper S. I used the specified fluids and oil change intervals. I had a ton of problems with it that cost an arm and a leg to fix at under 60k miles. PCV valve blew, low pressure fuel pump went, new ignition coils, valve timing chain and guide replacement, new main water pump, new thermostat housing... all and all it was 12k worth the repairs.... out of warranty... all at once. I had the work done by a BMW specialist and he suggested changing the fluid types as the car burned oil got too hot and casued the issues over time... and what was the recommended factory oil was too thin switched it to Liquimoly 5w 40 from castrol 5w 30, the coolant type he suggested was "Rowe" . I drove it for another 10k miles and sold it then bought the Fist because its just as fun (maybe more) and doesnt require a BMW tech of 150 per hr to fix... but still, Id like to take as good of care maintaining it as I can of it and want to use the best fluids for the vehicle.