Hi idlehands,
H/K AV receivers' power output tends to be very conservatively rated, so the 55 watts per channel should be ample. I presume your room size is "typical" --2,000 to 3,000 cu. ft--and we are not talking about an 8,000 cu. ft great room, with vaulted ceilings.
If the sound you are getting is clean and free from audible distortion, then your H/K is OK.
If upgrading to more power will give you greater peace of mind, then go ahead. You can't hurt anything. But remember that to make any meaningful changes in power output and maximum clean listening levels, you need to double or triple the amplifier's output power to 110 watts or 170 watts per channel.
Regards,
