[AceX]

Those 6x9 speakers aren't gooing to soudn worth a crap...

A 6x9 just produces too much low-end for what you want and have going in. You need something small to help out the mid and upper range otherwise it will be just pretty much bass.

Look into some 5.25" speakers in order to get better quality.

I would use the 4ch to run the 6x9's and a set of 5.25" components. Then I would use the monoblock to power the sub. I would also grab a high-output alternator to provide some extra juice, because those amps are going to draw alot of power when they start producing...

(I tend to go overkill on alot of things, so take everything I say with a grain of salt...)

At the very least, I would snatch of some 5.25" coaxials and run them off the 4ch amp along with the 6x9's. This would give you the best sound quality at a resonable price. You could also add the sub and monoblock amp to the mix in order to get the low-range that you want.

If you don't want to go out and find any additional speakers, then use the 4ch amp and run it as a 2ch and power the 6x9's and the sub.