automationgame.com

I know that convertibles dont have a very big share in the car market and would be harder to implement, but they definitely have some demand and would be an awesome thing to add to the game, like the MX-5, or the Honda s2000, these cars had high demand as well as success.

Yep, they're planned to come later on.

Are there plans to make cars with top down?

Convertibles would be easy enough to do with the top up, but top down would require some interior details which I thought was not going to be done, at least for current cars.

Top up only I'd say.