The first thing I think of when I hear "Porsche" is speed. The second: expensive. But what about a Porsche watch? Obviously, a Porsche timepiece doesn't tick any faster than a normal watch, but at $150,000, the car giant's latest chronograph is definitely pricey. Why so much cash? It's the first mechanical watch with a "digital" display, using numbered dials instead of hands to show hours, minutes, and seconds. It also has a power-reserve indicator to let the wearer know when it's winding time. That may not sound like enough to justify spending 150 grand, but inventors have been trying to make wristwatch innovations for 140 years, so I guess any first is worth a mint.