True but to get a difference in volume of 3dB ( which is what most people can concieve as a little bit louder) you need to double the power, so from 200 watts to 400 watts seems a big jump for a very little amount of increase, but if you add another pair of speakers you will have 4 speakers being pushed at 166 watts which will be much more than a 3 db increase,

I was just in the same market and this seemed to be the best set-up for me anyway, its better to add speakers than to ad amplifier power for most situations

Later dudes