I don't know off hand, but it's not really an important spec.
As long as it's not to low it doesn't matter.
A lower wattage efficient driver can be both loud and good quality.
The video logic sirocco crossfires are only around 20 watts/satelite and somewhere between 40-80 on the sub, and they are louder than the 400 watt ProMedias (a hell of a lot more expensive to, but that's neither here nor there).
Anyhow, I'm not trying to dodge your question, but I don't think BA gives out the wattage specs, but it also doesn't matter.
Go check out
www.3dss.com and compare dB loudness ratings. That's really all that matters. The BA4800 are quite loud regardless of what their wattage is, but not so loud as the ProMedias.
Unless there some reason other than loudness you want the wattage rating, I'd ignore them, they aren't a good measure of loudness.