Looking back at my original ideas I actually came up with some more that also might add more tunability and safety to the car. The first big thing is an adjustable lever arm and tensioned string system for the drive. What I was thinking is that in order to make sure we have the optimum lever arm we could use bolt, or a threaded rod to act as a lead screw adjusting the lever arm. Also along with this I'd probably stick the line through a shaft collar in the Lego axle also making it adjustable.
|Sketch in Notebook for Adjustable Lever Arm|
Another idea was making some sort of safety procedure to load and release the mouse trap. In addition I was thinking about actually making some sort of hook, or tool that would load and release the trap thereby making it safer for the user which no matter how old setting off the trap accidentally would be dangerous.