Hi. I have a 2009 Cooper S in Arizona. Temps are nice and cool now though...low 70's.
Is it normal for Mini S's to have cooling issues?

The car had been giving me the low coolant symbol every few days. It would be a little low and Id top it off. ...All better. Where's the water going? No leaks visible.
Then one time it was more than a quart low on oil, water too, and started smoking white smoke from the tail pipe really bad. But didn't say anything about heat. No warnings on heat. I filled up water and oil and let it cool and then seemed fine.

Since then, the car has been giving me the notices that the temp is getting high and to drive moderately and the later tells me to shut the engine off due to overheating. Even though I was driving super moderately. Why Isn't there a gauge? What the F is wrong with these people? Give me a heat gauge if nothing else on the car please!

Details: The coolant level goes down a bit and I have to frequently top it off. There are no visible leaks of any kind. The heater always blows room temp air not hot. It doesn't seem that hot actually.
My guess is that I have at a minimum, a head gasket leak. Water to exhaust port. (No water in oil.)
Does this sound right? Or,... somebody else said...water could be pooling somewhere internally because of a thermostat leak?
Is the gasket hard to do yourself? Will the head be warped? Is it aluminum? Hah. Okay that's a lot of questions. Sorry.
Anybody want to weigh in on this?

Thanks for your help!
John