There will be a feeding frenzy at the auction, and I'm not sure I'd want to witness it

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The ideal situation is to find a desirable older car through word of mouth or by chance, with a seller that is more interested in it going to a good home than to make a bundle. At an auction the popular cars will draw top dollar. The less fashionable ones (today) won't bring as much but might bring more later on down the road when they are more fashionable. Fickle tastes and all. Also, the market for old cars is cyclical. During the boom years of the 1990's they got quite pricey. During the recession collectors started selling off part of their inventory to generate cash. So prices dropped or remained flat.
It's also a truism that one can rarely get back what one has put into restoring an older, worn car, unless it's an especially rare and valuable model. And then some such are actually worth more unrestored (like old winning Italian race cars). The general wisdom is that it's more economical to buy a car that's already been restored. But where's the fun in that? ;-)
The flip side is that cars are perishable. So that nicely restored one will deteriorate over time. The rubber and leather will harden, the grease solidify, etc. To be kept in top shape they need to be stored in a climate controlled facility. Few average collectors can afford that. Of course I'm referring to the top rung cars like Deusenbergs, Rolls, Mercedes, Delahaye, Packard, Doble, etc. And to bring top dollar and concours honors they have to be restored to original configuration - no modifications allowed. It's quite an ego game played by the wealthiest collectors to whom money is no object if they can claim the Best in Show at Pebble Beach or other major Concours. Some of whom know little to nothing about cars but just want to show off.