It doesn't work like that. To properly run those component speakers, you need 75W RMS at 4 ohms per channel. The Mach amps cannot do this and neither can the head unit. You can run the component set off of the head unit, but the head unit is rated at 14 W RMS per channel. Not 200 like you stated before. 200 is the max wattage the HU amp can deliver at once to all 4 channels. Not very ideal at all.
To take advantage of the component set you want to use, get a proper amplifier to power them. If you don't want to do that I suggest you leave it as is. Not worth trying to make the Mach 460 work with what you're trying to do.
I thought about replacing speakers and doing what you're talking about with mine. I ended up ripping out the entire Mach 460 system and rewiring my own system from the head unit back.
35th Anniversary LE #1708 of 4628