One thing I've noticed is that the AC seems to cause a big drain on the 35d, more than I recall on previous gasoline-engined cars. When the weather is in the 40s to mid-60s, I can turn it completely off and open the sunroof and/or windows, and the MPG goes up by 2-3 MPG on my daily commute. The X5 also feels more responsive, although I can't say whether that is a real thing or just because I can hear more of the engine when the windows are down.

What's annoying is that the X5 (and many other BMWs and non-BMWs) insist on running the AC all of the time. I've heard the explanations/excuses that this dries out the air, blah blah blah, but I live in a very dry area, so that's idiotic. The X5 also doesn't appear to have a "vent-only" mode, and instead has to have the fan on to get any air moving. This air is apparently ducted through the engine bay or something, as it is always warmer than it should be. I love AC and the automatic climate control on the X5, but it shouldn't exclude being able to use it for vents.

One note on the trip computer, mine has never been accurate, and I check it against a manual calculation every time I fill it up. It's always lower than actual, and has been off by no less than .3 and as much as 1.5. What I wish we had was a digital readout of the instantaneous MPG, like I had on my e92 335i, instead of the 90's-era analog gauge.