I just finished installing a pair of Kenwood KFCXR601 dual mags in my '02. I was able to re-use the stock tweeter backing plate and the tweeters fit inside the stock housing. The mids, while shallow, required a 1/8 inch spacer for the stock hole, with no baffle cutting, and the mounting holes line up. Because of the basket thickness, I used 3/4" screws to mount the new speakers. The best setting for my ears was to put the crossover at -2 db. The x overs fit snugly but easily into the plastic recess in the door panel.
Initially I installed one side and A-B'd it against the stock speakers. The stockers sounded somewhat muddied, but the mid bass was more extended, although distorted. I think it reached a little deeper, and produced more volume, though not a lot, than the new setup.

After both sides were switched out though, things changed...a lot. The open clarity, while not quite as good as my Focals, is very close. I have a few AAD CD's, and am able to hear background noise and high sounds that were absent in the stock setup.
The bass is tight and hits really hard, with no distortion all the way to full volume. I autocross, and so I didn't want to add weight. I am using the stock head unit, and the Kenwoods actually weigh less than the factory units. I don't get boomy bass, but that it usually distortion. On the Sheffield Drum disc, the kicker and toms sound very natural and the cymbals are right on, and right there. I tried male and female vocals, and I like to reference with Aaron Neville, Linda Ronstadt, and Mario Lanza. Lanza probably had the greatest voice ever, and the stock speakers sounded like he was singing through a piece of cloth. No more. I am pleased with this setup, and although I will be installing rears this weekend, I am not sure it is required. I got my units from Ikesound and paid $159. A great improvement for modest cost.