Hehe, you guys will love diesel!
I loved my E90 330d so very much, I really miss the punchy torque and the fantastic sound it made.
As you'll likely know, the current 30d now makes 258hp and 560NM, along with being even cleaner and more refined, but let me whet your whistle with a video of my 330d 6MT (245hp 520NM) doing the 0-60mph sprint in 5.7s.
More power in the lighter F30 will be low 5's and the 530d won't be too far behind! The 35d (313hp 630NM) will be a real treat if you get that, and the 50d I imagine will blow your mind with performance and economy.
Even giving it some, the 330d never dropped below 44mpg (UK) really, and stayed mostly around 48mpg. Did an eco drive once (well, speed limit drive) and achieved 52mpg.