I put the 690's in the front doors and holy cow are they night and day better than the factory. I wouldnt recommend even replacing the rear doors or lift gate unless you're amplifying the system and summing the channels. As far as I can tell they don't get a full range signal, which is common nowadays.
The soundstage gets much louder and cleaner the harder it's pushed with the Focals. I'm very, very impressed.
For those of you on the fence about a $250 component set, don't be. The thing everyone on here is missing about just throwing in a $100setof 6x9's is, first off these speakers have a built in basket/housing to retain sound quality. If all you're doing is drilling holes in the door to throw a 6x9 with the back of the speaker exposed into the expanse of the door, you're losing 40-50% of your sound and especially the midrange bass, which is about all a 6x9 is good for anyway.
Here's a couple pics I took in the install, along with a teaser of the sub box I built. One of these days I'll hit 15 posts so I can start some threads for y'all...

Factory magnet... isn't it cute?!?