Quantity vs. Quality
I'm not sure what you're trying to get at, but in general unless you want 3 different sound systems, you can't add power that way. Also, you need to look at the true power of your speakers. There are continuous and max power rating. Typically the max power rating is 2 to 3 times what the continuous power rating is. Also, keep in mind that watts are not necessarily a good measure for receiver power. Look at whether the receiver has high current output more than watts, you'll be pleasantly surprised. There are a number of good receivers and amplifiers that you can use if you still feel you need more power. Your subs have little or no impact on power requirements because typically, if you have a home-theater setup, the sub is connected to the pre-out subwoofer connection (because the sub has its own built-in amplifier).
I'm assuming that you're using this indoors so, unless you have a banquet hall for a living room, I too can not see why you would even get up to 100Watts much less two or three times more. If you're interested, do some research on some receivers and you will see a number of good recommendations on this set. As someone else also mentioned previously, Outlaw amplifiers also give you good bang for your buck if you are looking at going for seperates. To get you started, take a look at these receivers:
- Yamaha RX-V 1500/2500
- Pioneer Elite 56txi
- Denon 3805
- Harman Kardon AVR-7300
Rotel and Onkyo are also good to look at for receivers. Good luck and enjoy the music!