I'm not 100% sure but I think I read somewhere that they are good for 60w continuous power. In my opinion, don't waste your $ on these. Better speakers for less $ can be had.
I've heard mixed reviews. Many who have installed the HD Boom Speakers have been very happy but I have also had some who did not like them. One customer in particular had a buddy with a J&M speaker/amp kit and one w/ the HD speakers and said that the HD one was better.