Hot wheels wouldn't be my first choice because of HS and HSII and not sure another car theme would appealas several have been done over the years. But wouldn't be against it if it was a great playing machine and some good ideas have already been suggested by previous people posting on this topic.
Personally I have no desire for an R rated pin as I have kids my own and other kids over to play pinball. However, if Stern made an great R rated game and then did the same machine with a family friendly theme, that would be fine.
Didn't Zaccaria have a machine in the 80s called Hot Wheels?