Our company does things a bit differently than a typical speaker company. In the context of what we do - direct speaker replacements for BMWs - the typical specifications are highly irrelevant to the end user. They ARE relevant during the engineering phase, however.
Take wattage, for example: A typical one-size-fits-all speaker company provides this information either to sound as "powerful" as possible or in order to allow a customer to choose an aftermarket amp to match the RMS of these speakers. This might be 50 watts RMS, 120 watts peak, for example, which means that the speaker can HANDLE a constant load of 50 watts, with higher peaks. It says nothing about the level of output or any other aspect of speaker performance.
What we do is very different. We design speakers to work off a factory amplifier that has a set wattage and impedance for each channel, and those values are very different from generic aftermarket values. For example, the factory amp may be putting out (in a Harman/Kardon E46 configuration):
32 watts @ 2.6 ohms - Midbass
24 watts @ 8 ohms - Midrange
12 watts @ 6 ohms - Tweeter
These values are are all over place. Furthermore, they vary between the "Standard" and "Premium" versions of the audio system, and they don't really tell the whole story, as we haven't even talked about the all-important efficiency values which would need to match the factory speakers - or the actual quality of sound reproduction.
Long story short, we decode this mess of information in the engineering phase, use that data to make the best sounding speakers for the exact system in your exact BMW, and then we shelve it - as it will only lead to confusion. Why? The general public typically wouldn't see "12 watts @ 6 ohms" as a good thing, even though it's the best sounding option for their car aside from fully custom systems in the $3,000 - $5,000 range.
Finally, regarding frequency range data for each speaker, again, this doesn't tell us much as we are working with the factory amplifier crossover settings - but typically, all said and done, you'll be hearing as much of the spectrum as humanly possible given the limitations of the factory system's configuration: about 50Hz - 20,000Hz