I just installed these in my car last night, and in growing fashion, here are my thoughts on it. Mods, feel free to move this to Aftermarket Products Review if necessary.

First off, these are the sturdiest looking and feeling 4x6s I have worked with. They have a relatively deep mounting depth of about 1.75" but also stick up from the speaker mount about half an inch, which is about the same as the stock speakers. Installation is relatively simple if you don't care much about wiring, but I took the time to splice on the appropriate connectors. Unfortunately, I don't have any wiring diagrams, as I have Monster wires running through the dash to the headunit. Stock wiring is pretty much the same, you just have to find the appropriate colors. [EDIT] It should be noted that you will need some longer screws to mount the speakers to the speaker mounts with their raised design. The stock 4x6 screw holes are recessed and use short screws that will just barely hold these plates speakers on. [/EDIT]

The passenger side is the easier of the two, as always. I had to notch the dash panel a bit to allow for the girth of the main component speaker, but mounting depth is no problem; all four bolts in the speaker mount go in as they should.

The driver's side is more difficult. You will not be able to get all four speaker mount bolts in without spacers of some kind, otherwise, you will flex the 4x6s and probably shorten their lifespan by doing so. I simply left the two bolts closest to the door off. The dash pad still mounts fine and I haven't heard any rattling. You will probably get slightly better sound quality by using solid spacers between the speaker mount and the dash.

Sound quality is 1,000 times better than the stock Delco speakers that were in there. The advertised frequency range seems to be about right, as the highs were crisp and you could hear much more quality of low-end instruments like bass drums. I felt that they began distorting a little too soon as I cranked them up, but that is more likely from the crappy headunit I have. I'll have to hear them with a good amp to get a really good idea of how much power they can handle.

Overall, I have been an Infinity fan for quite some time, and these speakers have not let me down. Getting better SQ or higher SPL is better achieved with kickpanel or door components with crossovers, but if you want high quality without spending TOO much, I definitely recommend these. I'll append more after I can get a better idea of their power handling with a better headunit, an amp, and/or inline bass blockers.

 

Hey, interesting....I was seriously considering these speakers. I have Kenwood 4x6 in right now and I'm not terribly pleased with them.

I just bought a Rockford Fosgate Punch 301 Amp....I'll review that when I get it installed!

 

I have the same speakers and they kick ***... for a few days I had taken all my amps and subs etc out and just had these in the dash with the h/u and I almost didn't care about the rest. I probably wouldn't even notice if I never had the 6x9's again, but they add some rear fill. My Kenwood deck puts about around 23 watts RMS and it can get loud enough to hurt my ears without crappin out. I've heard these speakers with an amp and they are a thing of beauty. Also I have, just messing around, held one of these in place where the 6x9's go, and they almost put out more sound and better bass... if not, its still very close. They are very, very efficient speakers, since I can run them astonishingly well off of 23watts. They are capable of 60W RMS, and 180W Peak. Range is 75hz-21kHz, and they are 4ohms just in case anyone needs to know.

 

I have those speakers too, as well as their 6x9 counterparts in my Z. i always felt, that, from an SQ standpoint, they had too much high-end treble, too tinny sounding, and not very good at bass in the 60-200Hz range.
As for running them off an amp, I have ran them off both a PPI PC4100 (100x4) and PC450 (50x4) and they took the power very well. Very underrated power wise because it took the 100 watts easily with no distortion at any moderate volume until they hit @ 200 hz or so.

 

They sure don't. But that can't be helped from such a small speaker. A 4" is more of a mid range then a mid bass speaker.

As a side note, I ran 75watts RMS to each crossed at 150Hz (4th order) without probs.