Surprisingly, my truck was stable at that speed. I need to make a wing for the back lol.
I've buried my needle a couple times which took a fairly significant amount of time to start moving again once I let out. Fairly sure I've not hit 140, since it still felt like it was accelerating when I let out. Never stayed there long, but, yes, they are stable 8,000 pound bricks.
Paint the wing black to match the bumpers.
Super car manufacturers spend a lot of money to put thousands of pounds of downforce on a car that goes 200, so you probably have a good point. I'd love to see one of these pigs in a wind tunnel at 200... I bet it's a sight to behold.
If you ever get the chance, video it and share!