Sub to Speaker Power Ratio

[BuckeyeInMI]

What kind of power ratio should I be looking at for a new sub/speaker/amp setup? My emphasis is much more on sound quality than quantity. Yes, I will certainly crank it up when a song requires it, but it doesn't need to be much louder than the stock volumes. I'm planning on doing an upgrade in the near future while keeping the stock Bose HU. I'd also like to keep the sub in the stock location, so it's gotta be an 8" that runs in an infinite baffle setup. Here's what I've got in mind.

Front Doors: Infinity KAPPA 60.9CS 90W
Rear Doors: Infinity KAPPA 62.9I 75W
Subwoofer: JL Audio 8W1v2 150W or JL Audio 8W3v3 250W
Amps(2): 4 channel class AB, 1 channel class D (specific models are for another thread)

I like the KAPPA series because they run at 2 Ohms. The Perfect 6.1's would have been nice, but at 4 Ohms they would require more amp power. Will the 150W sub be enough? Or will it lag behind the door speakers? Will the 250W sub be overkill for what I'm looking for?

[BuckeyeInMI]

Anyone have any ideas?