New 8 Series Cab (or 6 Series) vs 911

[amelen]

This is probably not the best place for this, but the best I could find. I'm on the market for a luxury/sporty cab. I've owned a BMW before, but switched to Porsche & Audi recently (mostly for the AWD). In the luxury/sporty cab market there aren't many choices though, especially if you need AWD. I'm looking at:

- Porsche 911 4S Cab
- Audi RS5 Cab (won't be produced)
- BMW 8-Series/M8

I know the 8-series & M8 isn't out yet, so I wanted to get the opinion of the current 6-series cab owners (probably the closest to the upcoming 8). Did anyone cross-shop with the 911? What made you go for the BMW?