This is a complete remix of the awesome Dual Mode Windup Car by Greg Zumwalt.

One of my childhood favorite toys was a model of Herbie, the love bug. So I wanted to draw a remix that reminded me of it, although later I followed the New Beetle design more closely.

Greg rightly notes in his comments that weight has a lot of influence on the performance of this toy. I noticed this with the first heavy prototype.

I then redesigned the gears set, enlarging them to accommodate a bigger and more powerful spring.

Initially, both for greater smoothness and to improve mechanical tolerances, I created a model that includes 10 ball bearings: no. 5 10x15x4mm (6700ZZ) and no.5 6x12x4mm (MR126ZZ). You can conveniently replace the latters by properly cutting Igus Iglidur 6x12 bushes as you can see in one of the attached pictures.
But I realized that the bearings on the wheel axles were not as sliding as the plastic bushings.
So, although the drawing remained the one to use the bearings, I designed bushings to eliminate the bearings.
To those who object that this increases the number of pieces and complications, I reply by saying that bushes wear out over time and that it is better to reprint simple bushes rather than a side body with worn holes. I get the best results by printing the bushings with PET, which is perhaps the best material also for printing the spring.

Another complication with respect to the original design is that it is necessary to thread several holes (M3), those on the wheel axles and those of the three spacers that hold the side bodies together. But thanks to these screwed spacers, a strict tolerance on cross members is no longer necessary. 

To avoid collisions with the rims, M3 round head screws should be used in order to tighten the spacers to the body. 

I designed a different rim, with a central locking screw: any M3 screw can be used to lock the rims to the axles.
For the tires I was inspired by John Corkery's remix, published on Thingiverse. I designed the tire with a more curved profile, to reduce the footprint and reduce friction. Better to use a soft flexible filament to print the tires because the high initial power combined with the weight of the model could cause the tires to slip on very smooth surfaces.

For those wondering what is the reason for the strange design of the recharge key, I did it to be able to insert it under the body top during transport, as seen in one of the attached photos.

Finally, I included step files for all the elements you might want to change according to the output of your printer.

I did not count the hours needed to print the model, but we should be on time to have it ready for Christmas gifts.

 P.S. if you like, you can customize the model by printing handles and lights separately. You can also create a personalized license plate by modifying the corresponding step files that you find in this following additional remix.