You know, I don't know why they do that. It seems kind of rediculous to me too. I've got some stuff I'm going to put on there later this summer that I'm not going to let go below a certain amount, but I'll start the bidding at my minimum.
What I usually do on stuff I'm interested in is put the item on my bidding/watching list and just check the list periodically to see what is finishing up soon. If the price goes over what I want to spend before the bidding is over, the item gets deleted from the list and I forget about it. I have no intentions of getting caught up in a last minute bidding frenzy and spending more than I was originally going to. I don't place my bid until about the last minute or two of the auction unless I can't be at the computer when the auction closes. Even then I won't go over my preset limit.
When I first started bidding on Ebay I got into a couple of last minute bidding wars and ended up paying more than I should have. Afterwards I thought, boy I paid more for that than it was worth, but I WON by Golly! Guess I showed those other bidders! Stupid, huh!
You can get some decent deals on Ebay if you have patience and use some sense. Don't know if all this rambling will help you, but that's my philosophy on Ebay bidding.
Hope you find your car, it sounds like a great project!