I use 35 watt 4300K bixenon HIDs from HIDcountry.com. They work well and give a lot of light with a well-defined cutoff. I think there is a point of diminishing returns if you have to worry about damaging your expensive headlamp assembly, not to mention you share the road with other drivers. I have installed many of these sets in cars and motorcycles and have not seen any damage of lenses or reflectors. I have no experience with 55 watt units. I do know of damage resulting from an individual who improperly installed a light in a way that the capsule was not properly secured in the base, and arced to the shield and reflector.
I'm not an expert with these, but an HID lights create more light with less energy works by striking an arc between electrodes in a capsule filled with inert gas (xenon). The arc generates much more light than heat. A filament bulb works by creating resistance in a tungsten filament that crates heat. As the heat intensifies it glows, The more current you try to pass through the filament, the greater the resistance and the more light. You don't need that with HID. I think if you introduced more current (watts), you might be able to strike an arc across a longer distance, which might support a larger HID capsule, but this could be a problem for aiming the light. I don't see the point, but on the other hand, I don't see a lot of complaints or problems with the higher wattage units being reported in the internetz either. . If there was a bunch of damage happening, you'd probably see complaints pretty quickly.
