Sylvania IS Osram, and vice-versa. Opinions vary as to whether the Silverstar product lines are the same bulbs, though. But it's the same company. I believe Sylvania bought out a European company some time ago and continues to market as "Osram" in Europe for the name recognition.
Various high quality bulbs, including illegal overwattage ones, are available from Daniel Stern Lighting. (Google it.)
There is no such thing as "brighter" halogen bulbs for a given wattage, but well-made bulbs might put more light on the road because the filament is more precisely located. You want to avoid anything with a blue tint. That's just a scam to make the color look like HIDs, but any tint on the envelope just reduces the actual lumen output. And don't buy into the "Xenon bulb" scam, either. True HID lamps are filled with Xenon, which is one of the most expensive commercially available substances in the world, but the only reason to put a meaningless amount of it in a halogen incandescent lamp is for marketing purposes. It has no effect.
55 watts is 55 watts no matter who makes the bulb, but quality has other benefits besides the amount of light the glowing filament produces.