Well, before I actually found out how easy the wheel was to replace with the spare, I thought about PE wheels too. The rest of the car has such spotty and mediocre detail, I'm kind of glad I didn't have to. For example, there's a hatch in the head rest fairing for access to the fuel cap. You can barely tell it's there on the old car. The chassis and engine detail are pretty good, but why didn't they hinge the hood? No wonder so many of the latches and buckles are missing from the ones for sale on eBay. Finally, the dog legs for the door hinges are gigantic. I'm just glad I didn't pay full retail from DM when they were new.
Don't get me wrong, I like the little car, and it fits in with my attempt to collect cars of the fifties. If you want to put PE wheels on it and add decals to make it unique, I say go for it.