I was also surprised by this. My Z4 has a water temp gauge and I just assumed the X would have the same thing. Personally I would like to have both an oil and water temp gauge. I could give up the stupid swinging fuel economy thing anytime. I always wait for the water temp to come up before I get on it in the Z4 but still wish I had the oil temp as this would be a better indicator of engine temp and if I recall takes longer to heat up than the water temp.

That being said all car purchases are a compromise and I have never bought a car that had everything that I wanted or the way I wanted it. When I can I custom build a car on the web?