nah, i beliebe B's set up is like dubling the RMS rating lol... you can do it.. but some companys void the warenty if you over power them to much. you can do it as long as you aren't like giving a 200 RMS sub 600RMS
how much you talking about? i ran 600+ to my r's and they played perfect and their rms is 500. just dont over do it and your good. and probably depends on the brand, so if you have a cheap piece of sh!t i woudn't chance it.