Finally, got time to build this model but it's a challenging build with two kids disturbing me, hiding the technic pieces, etc.
Two bags, two manuals and two kids...

I hate putting up stickers but looks nice after putting on.

Only 3 small pieces left when done:

The steering mechanism is without any gear. The steering and the front part of the go-kart is a little flimsy.

Both wheel at the back turn simultaneously.
Let's compare with the other models... the first is the buggy, then the go-kart and another go-kart but very old model (Should have two lights in front but I lost one, so mod it become one light only.

And here is the rear side of them. The buggy has 4 cylinders in a V4 combination, the go-kart only one cylinder and the old one none but has a suspension.

Overall the build is easy. Only took me about 20 minutes but should be faster if not because of chasing after the kids to get parts to build. Construction wise is a bit flimsy especially the front part that holds the steering.