Sorry about those who can't see the pictures. When I get more time I'll probably just get my own site again.
I finished my wife's install today. I can honestly say, the Infinity's seem far superior to the Alpines. I wouldn't pay $270 that Crutchfield wants, but the Amazon pricing of $170 for components and $100 for coaxial is a steal.
The Alpines, however, are a better fit. Don't get me wrong, they both screw straight to the adapter, but the Alpines, sit perfectly over my speaker brackets' openings. The Infinity OD is a tad smaller making gasket/seal installation a little more frustrating. Also, the size of the crossovers for the Infinity set make them a little more challenging to place. With a little persuasion, they fit inside the previously pictured armrest slot (they're 3 1/16", and the armrest area is exactly 3"). Keep in mind I didn't install crossovers for the front.
So, for quality of sound, I would choose the Infinity speakers. For the ease of installation, I would choose the Alpines. If price were close, I personally would go with the Infinity and deal with the install.
As for the coaxial fronts; I was reluctant to try this, but I figured if it were easier and saved some money, I'd give it a shot. My wife and I honestly agree that it is not adverse to the sound field. I think some songs sound better than my setup, and others I would prefer my full components and programming. I unplugged and insulated the front tweeters on her car.
The coaxial fronts seem to bring a little better balanced mids to the table, but seem to sacrifice a bit of the higher low frequencies. The directional tweeters make a pretty big difference depending on where they're aimed. I was able to adjust the mid on the EQ up 4 notches (-7 to -3) from where we previously had it, and it doesn't kill my ears. I also was able to center the fade (at 1 to the rear previously).
The car, at least where she and I sit (I'm 5'8"), is very balanced in sound now. She was ecstatic when I let her test it out. She doesn't know brands of speakers or care about audio talk. I feel she's a good slate for an opinion. Her opinion is that it now sound 'more full', and it 'doesn't sound like it's all coming from up front anymore'.