These speakers did exactly what I hoped they would do - clean up the sound from my factory stereo, and utilize it to the fullest potential. I upgraded the front door speakers on my truck ('06 Ram Quad Cab) first, with the 6x9 version of these speakers. If I were to do it again, I'd replace all 4 speakers at the same time. These 6.5" speakers fit in the factory opening in the door, but I had to drill some holes as the factory screw locations did not match these new speakers. Another note - my truck was wired with the rear speakers out of phase with the front, so I had to swap the polarity on the rear speaker wires. A pretty common thing to happen on the 02-08 Rams, I hear. I elected to swap the polarity on the Crutchfield-supplied speaker wire adapters, as that was much easier to access and modify than the wiring in the door pillars.
As for the sound of these speakers - the high notes are a little bright with the factory stereo, just like with the 6x9s. I suspect the factory stereo uses an exaggerated treble curve to compensate for the factory paper woofer's lack of high frequency response. The sound from these speakers are what you can expect out of a 6.5" speaker - not very deep bass, but the bass that's there is clear and tight. Mid tones are great, too. Not muddy at all. These speakers complement the 6x9s up front very well. Good balanced sound and it no longer feels like you've got cotton in your ears with these speakers. I was amazed at the difference!
Pros: Great clear sound for the money. Makes good use of the factory stereo's power output. Crisp highs, clear mid tones, tight mid-bass. Crutchfield supplies wire adapters to fit the factory wiring. Would sound even better with a good aftermarket deck - a great incremental upgrade for those of us who have to upgrade in stages.
Cons: Had to drill holes to mount in my '06 Ram's rear doors - not a big deal in my opinion. The sound out of these speakers was so good that I finally realized that my truck had the rear speakers wired out-of-phase from the front. Once switched, all 4 speakers worked together instead against each other. Odd, because I never noticed the out-of-phase problem with the factory speakers - probably because I couldn't hear them very well.