In my O6 I ran a pioneer double din with nav and was really happy with it. At the time the alpine was too much money with the nav or I would have gone that way. I replaced the factory trim bezel with one from the same year that had nav and got a double din dash kit for it and the install was really clean looking. Also unrelated I ran a memphis M class 5 channel. It was as long as the 60 side of the seat, but narrow enough to fit on the floor between the back of the cab and the the screw down plate tucked under the back of the load floor, which was still left installed and fully use able. I ended up going with it for the perfect fit, but it was a beast for power and ran my Fokal front and rear and 13" sub in the 40 side really well until I blew the sub from overpowering it and switched it for a different sub that worked better given the amount of power I was running, but I can't remember what it was.
Nice. I've recently pondered the idea of sticking with stock sized speakers all round, adding 3.5's to the dash, running those as 'fronts' with the rears as 'rears' and the front 6x9's as 'subs' on my headunit outs. All amped to their limits with the HPF and LPF handled through the headunit. Seems like with maximal sound deadening, it'd be a REALLY good low profile, simple, no space taken setup.
And then I learned that this is almost EXACTLY how the damn infinity system works!
But it really does seem to be an idea that has merit. If I could, it'd be 6.5's rear, 4's in the dash, and 7x10's in the doors as 'subs'. All coax except the 'subs' which would be gotten as components and had the tweets spliced with the fronts and probably put in the pillars from a plain drilled hole.
But anyway. This is about my rant and headunits in general. Really, aside from the small issues that have loopholes, and this thing that I believe I found the source of and easily fixed, {and not having a 'mute' button} this Kenwood is actually pretty cool. It has preset EQ's, 13 band custom EQ, bass boost, loudness, realizer, other effects, x-over, the ability to tell it what size speakers are being run, what type of vehicle it's in, time alignment. It's actually, in my novice opinion, a good single din.
If it didn't have the little loop-hole-able problems, greater USB compatibility for a wider range of phones, and a mute button, I'd venture to say it might be the best single din. Now, lemme look in the manual and see if I can just plug in a USB flash drive for music, hmmmm.....