Found it kind of odd that there was an undo and redo button, but no hotkeys. Why not hook up a button press event to the redo and undo functions?
There are hold and revert buttons. Not only can you revert any changes made but it also compares the stats from when hold was pressed so you can see if the changes you are making are beneficial.so just press the hold button, make some changes see how it will affect the engine or car then save those changes or revert and try again.
OP is asking about the new Undo/Redo buttons on the lower left corner of the screen with the most recent major update. As for adding them to a hotkey, are any buttons in Automation on hotkeys? I thought it was entirely mouse driven, as in no keyboard required other than naming things.
Not difficult to do and planned already. There will be a bunch of hotkeys added eventually 
Good to hear!