brand X bulb CAN be brighter than brand Y
robert, you are correct sir: lumens is the measurement of output.
thus, it is possible that brand X can output more measurable light than brand Y at the same rated wattage bulb.
true HID lights ouutput more light (or at least in what they advertise as being in a more useable spectrum) at rated watts that are close to 55W as is utilized in most "conventional" systems.
as for being homologated, as used in racing jargon: auto manufactures are required to produce a certain number of cars for sale as retail units for the cars to be considered true production models in order to be "homologated" or approved by the sanctioning body. this is as opposed to one-offs or specials.