You did nothing wrong and eBay worked to a point, what failed is a deadbeat bidder. He has admitted that he had no real interest in buying the car, but bid anyway just for fun. Well in any real World auction he'd be buying that car or being sued, unfortunately this is one area where eBay fails and more people are bidding on items they have no intention of buying.
If the bidder had really been surprised he hit the reserve then he could have retracted his bid immediately as there is function for that. Instead he let it ride 3 days until the auction ended. You must contact eBay and file a non paying bidder report, or you will be charged selling fees as in their eyes the auction completed and the deadbeat gets to go ruin someone else's auction in future.
I have had items relisted on eBay 3-4 times, eventually you get to the right buyer, just bear with it. Don't forget the auction also ended over Christmas and many people are focused on the holidays and family.
Personally I also think you'd attract more potential buyers if you went ahead and removed the roll bar, reinstalled the oem seats and an all black steering wheel, although you offer to swap it out many buyers can't see past what's there.
The market may be softening a bit, all stock is still fetching the big money, it will be interesting to see what the 6 Pantera's at Mecum in January fetch.