The Ferrari looks nice. The wire wheels look great. I bought some wire wheels to change over to, but haven't got around to it yet.
Looks like you have a Minebea S can in there. The 8/20 gearing suits that motor well. It has good torque for a tiny motor, and I would think this car drives well. My experience with this motor and gear combo has been good. The good braking and smoothness of the drive result in good times, even though you don't have the high RPM of alternate motors. As long as you are not racing on a course with a long straight, this combo can keep up. These motors are rated for 12 volts, and run cool all day long
FYI The tires I cast sand off well. After gluing them you can sand them down to the required OD.
Again this is one of my favorite cars, and even with the problems you have encountered the end result looks great.