I would get the higher rated filter. You never know what you may add to the system over time. The filters just consist of a couple of capacitors and chokes, the same circuitry (not rated as high and not the quality) that a very high end audio component would have built into the power supply.

Just as an FYI: I had a 5 amp filter on an 7.2 amp device and the plastic parts on the chokes have all melted. So the moral of the story is do not push the ratings of the X10 filters at all.