ha, someone paid good attention watching that episode of Top Gear. Great episode though, was it not the same one when they battle the 3 germans and show up in World War 2 spitfires and everything?
And yes, the gumpert may look like shit and have a strange name, but it's designed for speed. Every part of that car is built for performance. If i remember right, you can't even adjust the seats because it will throw off the center of gravity.
And supposedly they have found a tunnel to test it in upside and have found a way to mod the engine so it will run, but the only problem is that no one is daring enough to drive it during an upside down test.