I live in a all year warm climate (70F - 100F / 21C - 38C). I really don't need antifreeze. Is there coolant only option recommend for a 2008 R56 MCS.

How much coolant would I need?

 

How about water plus Redline Water-Wetter?

 

Coolant / Anti-Freeze does more than just prevent your cooling system from freezing. It also lubricates and protects the cooling system components, and helps increase heat rejection in the radiator. According to BMW/Mini, the ideal ratio is 50 / 50 mix of coolant / water. Too little coolant and corrosion protection is reduced. Too high ratio and heat rejection properties are reduced.

 

BMW coolant. It's relatively inexpensive and can be found at any BMW dealership. It is formulated to not harm the alloys used in BMW motors. Mix it 50/50 with distilled water. The coolant capacity of the car is about 1.5 gallons, so you're only going to need a single gallon of the non-diluted coolant.

 

Zerex g48 is the bmw/mini specific coolant that you should be able to find at any auto parts store, already pre mixed.

 

Yeah, you absolutely want to use antifreeze for corrosion protection.

If you live someplace warm you can go to a 40:60 mix of water to antifreeze. This boosts cooling system performance at the cost of a higher freeze point (-10F vs -37F) but if you live someplace warm the freeze point doesn't really matter.