That's pretty clever. I would have never thought of that axle techniqe. Wile it's a shame a minifig wont fit in your car. I took on the challenge downloaded your ldd file and tried to see if i could finda way to fit a minifig. And i believe i managed to do it. I'll post some pictures later today.
That car is really cool, I love the concept of turning real cars into proper LEGO cars. I think I might have to try to build one myself. But i'm curious, is there a reason you used another building tenique on the front wheel axel?
I'm not really sure what my first lego set was. Since my household had already a lot of lego and me and my sister who was into lego too shared the lot. But I have been told that my sister got this set the same day I was born. So I guess that could account for something