I hear mixed opinions on biwiring, but most audiophiles tend to agree that biamping is advantageous. For now, I have technical questions about this...

If a speaker's power handling tops out at 150 watts of power, is it a true statement that the most power you can achieve is through 2 biamped 75 watt channels? In other words, do you combine the wattage from both of the amp's channels?

If so, the problem Im having is understanding what is better about this approach. I mean, my Onkyo receiver drives each channel at 100 watts, but I would imagine I'd have to downgrade the overall power of my system if I biamped one speaker (like my center) @ 150 watts and left the other speakers amped @ 75 watts. I guess I'd prefer 100 x 7 here, because any way around this sounds awful expensive (Multiple amps= $$$$). Yet and still, is 75 watts from an amp better sounding? What is the solution for a budget minded buyer like me?

Keep in mind I've been looking at this in terms of power alone. I know that the overall quality of the sound is subjective. I'm aware that some of the integrated amps in receivers can pale in comparison to a true dedicated multichannel amp or a series of monoblocks (in terms of sound and build quality). Know that the reason I'm even considering power amps is because I'm assessing whether an upgrade would be worth it. Using my receiver as a preamp (the more I read about it) is getting tempting. Any comment here would be helpful.