Lose money on a (classic) Lotus?

[Tuna]

I've had an Excel before, which turned out to be a cracker of a car, and went for the same amount I bought it for, and I look back at the S1 Elise with fondness..

.. so the question is, how much risk is your money at if you put it on a classic (or at least, not brand new) Lotus?

Obviously there's risk of a catastrophic rebuild cost, but for a car in decent nick, driven regularly and responsibly, it seems to be less expensive than depreciation on anything shiny and new, and potentially cheap-as-chips motoring.

Man maths or minor miracle? What would you buy?