Euro F10 523i vs US F10 535i vs E60 535i
Long story, but I got a new US spec 535i (F10) in Munich July 1 which promptly broke and was replaced by a Euro spec 523i (F10) rental. In total, I put 800 mi on the 523i on the autobahn, and about 600 mi on the US (F10) 535i. Just got back to the US, so I am back in my E60 535i.
Although the 523i has about 100 HP less than the 535i, it drove well. I did notice the lack of power when trying to accelerate from an already high speed (say, 80 mph). It always dropped a gear or two and worked hard in the 4000 to 5000 RPM range. Nonetheless, it could run at 120 MPH very nicely unless there was a hill. There were two distinct advantages to the Euro spec car; first was the convex driver's mirror which practically eliminates the blind spot. I don't know why the US puts the convex on the passenger's side only. The second was the real-time speed limit system which senses roadside signals to indicate the current speed limit. This is critical on the autobahn where it can go from "unlimited" to 120 km/h to 100 km/h or less in a very short space.
After 4 days with the 523i, I got my 535i back and was frankly shocked by how quickly it accelerated with just a touch of the gas after having got used to the 523i. The 535i just accelerates effortlessly. (I imagine I would have the same sensation going from a 535i to a 550i.) The 523i is adequate (about like my old E39 528i), but more is better, I guess.
The F10 just feels like a bigger car than my E60. I think a lot of this is the length and shape of the hood. I just got out of my E60 and realized that because the hood slopes down, I don't even see much of it, but the F10 hood, with its creases and lack of slope, is just in your field of view all the time. Both F10's I drove had adaptive suspension but neither had 4 wheel steering. No matter what setting I used, the steering on both F10 felt considerably lighter than that of of my E60 535i Sport. Nonetheless, both F10's felt quite solid on the road up to 110-120 MPH, but conditions on the autobahn were such that I didn't feel comfortable going any faster.
The iDrive is much improved on the F10, as is the Nav. I would highly recommend the adaptive speed control, and I also liked the blind spot detector. Both worked extremely well, but you have to get used to them. The lane deviation feature (which comes with blind spot on the US, but not the Euro) is kinda goofy. The active ventilated seat is a must in very hot climates (and it was very hot in Germany last week), but the active butt massager takes some getting used to. It is kinda like suddenly feeling that something fairly solid is moving through your underwear, but not in a good way.
Anyway, it was a real experience to extensively drive these 3 cars over the course of 10 days. I would be happy to respond if anyone has any questions.