Will I lose my shirt on a 650?

[mdrc]

I'd like to buy a 650S Spider now, whilst waiting for the 720 version to be launched, but fear I'll lose my shirt on a nearly new 650 over the next 12-18 months......there seem to be a few that have been on sale now for as much as 3 months and they don't appear to be shifting.....as the 720 cars begin to come off the production line, I sense the prices of the 650s will fall dramatically......but I'm happy to bow to the superior knowledge of you expert McLaren market observers.....(PS I do expect to suffer some depreciation!)