Womble
I don't know of any good deals - Go along to your nearest BMW dealer on 8 Mar for the launch - however having seen the photos and having looked at the figures I think that the 650 may be the dark horse. Here's why:
1. Only a drop of 15 Bhp over the 800 - And made at lower RPM
2. Still some 70ish NM of torque - And at lower RPM than the 800 (4750vs5500 I think)
3. Better looks - In my opinion anyway
4. Lower price - Giving you more scope for the inevitable BMW accessories which will follow.
5. 19" front wheel allowing greater choice of road-orientated rubber.
I wouldn't be surprised if the 650 turns out to be just as effective, if not more so, than the 800 version out on the road.
Let us know how you get on if you give it a try.