Sorry for being so stubborn, but I really want unitPlay on this. I was looking into removing the sound when I found this:
https://community.bistudio.com/wiki/sendSimpleCommand
It allows me to send the 'fast' command that minimizes when the tires skidding.

Also, I think I found a solution to the crew being slouched over, I noticed when I swapped positions back and forth with the driver, he perked up. I should be able to teleport all the crew out of the vehicles on unitplay start, and then teleport them back into the vehicles. I will post back here (if I remember) when I get to it. It will probably be a while before I do as I have a few other things in this intro I want to sort out.

Once again, Thank you for the help BroBeans, PierreMGI and 654wak654! Without your suggestions I probably wouldn't have found the sendSimpleCommand command.