im running a 800W monochannel audiobahn amp. with 2 12" audiobahn subs, w/4ohms and both are 400W/ea. im wanting to get 2 800W to run at 2 ohms so it would be hitting 2x harder...man and right now its making my nose tingle and feel the wax in my ears moving...lol i love my setup and can't wait to upgrade my subs for it... amp was refurb, and got it for 140 w/ 1yr warranty. stereoneeds is the seller i believe..
The speakers are 5x7/6x8's (they are the same size, the latter has as slightly larger cone).
What are you goals for your system and what is your budget? Both of these are determining factors in what I'd recommend you go with.
As a general idea though, look for a solid two-way coaxial speaker or component set. Typically, a quality two-way will outperform the three and four-way speakers that you see. To give you a place to start, Polk's dB series (Polk dB 5701 and 571 I believe are the models, but don't quote me on them) are good all around speakers. They have a pretty warm sound: not too harsh of highs and not pounding lows. Also, check out some of Infinity's stuff. Their Kappa line is what I'm using (mine are ~three years old), but from what I've heard, they still are great (Kappa's). However, they will require some tuning, as they are rather "bright" in that they have a lot of treble/vocal emphasis (or at least they were when I bought mine..I haven't heard the newer ones). This can be taken care of with some tuning on the deck's EQ though.
There are a lot of options for subs/amps/decks as well. I'd recommend a single 12'' with a matched (power-wise) mono block amp. In the Focus, unless you want ear-splitting bass, you really don't need more than one sub, especially if you get a quality one.