I took my diesel for a test on a larger road yesterday.
I couldnt make it run more than 218km/h. And those of you who tried and unlocked the extended DIS know that the effective speed is actually lower than the one reported by the speedometer. Tank allmost empty but 2 friends of 90kg each onboard.
Actually, i dont need to go that fast but... just for the record!

 

I had my 530d up to an indicated 140mph on the straight bits of the German autobahns last month. The car felt solid as a rock. I was *cruising* at 120mph for much of the time and enjoyed the corners big time (even though I don't have dynamic drive). And I averaged 30mpg!!!

 

on a long stretch of road (I5) north of LA I took mine up to 142, OMG... and there was plenty of room left at the top. What a wonderful car. Solid and stable. Typical highway driving I'm getting 28+ mpg.

 

The 530d from the BMW dealer that i tried before ordering mine, almost reached the end of the speed meter. About 240 Km/h, 245 Km/h.
I tried two cars. Manual gear box, one with Dinamic Drive, other with regular suspension.
Do you have auto gear box? Maybe the question is there.