Porsche is hard at work putting the finishing touches on the first-ever electric Cayenne. It's a big deal for the German brand, as the big SUV is one of its best-selling vehicles, so it has to be as close to perfect as possible. There's still a lot we don't know about the electric Porsche Cayenne, but now that the first prototype test drives are done and dusted, we have a better idea of what the flagship electric SUV will be capable of.