Ahh, I do like that a bit better. It's a bit easier on the amps, and your power system. The class D mono won't **** so much power, and it's more efficient. Don't want your alternator to start struggling.
My only comment now is that the 2 chan might be a bit weak.
To save some money, I'd say something like this -
http://www.woofersetc.com/index.cfm?fuseaction=product.display&Product_ID=374
Then, with the subs, have them wire it down to 1 ohm. You'll put more power for less through them.
Then, go with the better two chan -
http://www.woofersetc.com/index.cfm?fuseaction=product.display&Product_ID=3952
It does, however, put you about $50 more than what's there. But you'll have quite a bit more power.
Wow, like 5 posts while I did this -.-
Ahh. Focal comps. Those will take less power, so you can ignore my suggestion on the better two chan, and go with the smaller one. Put you right about even again, I think.
And I'll add another thing. The mono amp means it puts the same sound signal through whatever it's powering - it's not a stereo/surround sound. You can power multiple speakers in one channel too, it just means they put out exactly the same sound. Hope that clears it up. For the bass, you don't need a stereo sound ^^
Honestly, now, the only thing I'd be unclear about is the subs. I don't know how good those are. One possibility would be to go with one type R, however, a dual 2 ohm version, wire it to one ohm, and power it with the memphis amp. You'd be putting rated power through it, and it *should* be cheaper.