There is another thread on 930vs3.2 if you search - I started it after driving a 930 just to share my thoughts.
Purely as a driving experience, you have to decide if you are a "Turbo guy" or not. The 930 is not a modern small turbo with fairly instant response from virtually all revs. It is old style and packs a big bang in terms of boost and on-boost torque. Because of the 4 very widely spaced gears you find you are often off-boost even in first and you have to wait for the boost to come in under normal driving - and it doesn't come in until 3500rpm. Last time I drove one I found myself downchanging into first for roundabouts so I stayed on boost. It does 60mph in first. The widely spaced gearing means you don't change gear all that often and the sound of acceleration is diminished - you pick up speed but the revs are not rising all that quickly. Fourth is good for a theoretical 180+mph, so you effectively have a 3 speed gearbox with a cruising overdrive on top. Best thing IMHO is the engines run rich on overun and make a cool "pop, pop, pop" sound as you lift off - especially with a sports exhaust.
I generally like old school turbo engines - think 5 cylinder Audis, 924T and older Saabs - because the midrange torque is so dramatic and the on/off boost/lag characteristics add another thrill to driving, however, after a stint in a 930 I didn't find myself wanting one. I certainly don't think they would be much faster (if at all) than a good 3.2 in general driving.
The wide track and big brakes are nice but the extra weight on the tail is not. Otherwise handling is kind of similar. You notice the extra weight all round in the 930 - it really digs its tail in and squats under boost. A 930 would be quite a nice car to travel across Europe in, but strangely, I think the 3.2 is more "sporty" feeling. I like throttle response and the 3.2 is a long way from ideal (try an old MFI engine for that) but its much, much more responsive than a 930. A modified 930 with less weight and more power would be nice - but I assume that is not your question.
Bottomline is you need to drive one - 930s are cool cars, but they don't suit everyone.
Perhaps someone else may comment on running costs, insurance etc. I spend too much money on non-routine running costs/upgrades on my 3.2 so I hardly notice the routine stuff.
]), the brakes are good rather than brilliant. 
