Some UI ideas

I know the UI is a bit full, but I think the addition of a "quick test" would be great. Instead of having to click the Testing tab and "Start" then "Skip" to get some results, the single click would make it much easier to see the results (perhaps on a constant results frame set behind the part info panels that you can hide,) and make quicker adjustments. The testing tab can show the power curves and do the revving animation, but when you are trying to make small tweaks, clicking back and forth gets very tedious.
I also would love to see some sort of "undo" button so you can undo anything you changed since the last test you did.
I also would love to see some sort of "undo" button so you can undo anything you changed since the last test you did.