Like Derek said, I think it depends on the car.
Say for example you have a guy selling a well put together 6GA that has about $30K into it as far as performance parts go, and then you have a guy selling a well put together mkIV Supra with $30k into it as far as performance goes.
In my opinion, the Supra is going to sell before the 6GA because there is a market for Supras. They are uncommon cars and twenty or so years from now, you're probably going to see these cars rolling across the auction block at Barrett Jackson. A modded 6GA? Not so much. This goes for pretty much all mass produced easily attainable cars.
An exception to the above may be special editions, and no I don't mean Accord SE's. I mean cars such as a first model year Evo VIII (first year in the US), first model year WRX, Evo VIII MR, First model year STi, SVT Focus with the euro package, Saleen Mustangs, 1G Impala SS, F Body Camaro SS (the white ones with the orange rally stripes), Nismo 350/370Z's. I think you get what I'm saying.
I think the above applies to the majority, but then there is always the minority, the fanboys like Roy said, that will overpay for something even though it's worth only a fraction of what they paid. Those people are idiots.