That will be fine. It's always better to turn the gain down than up. 100W isn't much difference, and it's always better (and cleaner sounding) to have more amp power and not use it instead of trying to stretch a lower powered amp into it's high distortion range.
You have a little room to work with if you want to go with bigger or beefier subs too, or go to a sealed enclosure (which sound great but don't have the best efficiency).