I'd pick up some OSRAM SilverStar's from a European dealer. (Sylvania = OSRAM, just different company names depending where you live.) The US Sylvania SilverStars are +30% brightness, the European version is +50%.

Note, obviously, the European version does not have DOT/SAE certifications, but if it were tested, it would most likely meet their standards. They're certified by the European equiv of our DOT.