Hmm, looking at prices:
C180 about £40k
C170 about £30k
C140 about £20k
Hard to see why the C140 is that much less fun for everybody than the 170 and 180, and they're all just as good looking.
I think that fun 'though the Thurston Teal looks, Silvaire's C140 does sound like a jolly good option. Presumably similar running costs to a C150, but nice?
G