Personally, I wouldn't be as concerned about the wattage as the heat generated. After all, the stock bulbs are 55W halogens so obviously, the electrical system can handle it. AFAIK, most of those upgrading to HID are going with 35W bulbs. With that setup, you use less power and enjoy far greater light down-the-road. The best part of that upgrade is not melting the reflector housings .