I'm going to update this thread by saying some things some people might not like.
1. You get what you paid for. Kicker does make good speakers, but the ones as seen in the "premium audio for $250" thread are not premium.
2. Some people are satisfied with the kicker components that are referred to, others find it to be to "bright", and still others will find it to be not powerful/full enough.
3. There are much better speakers out there, good quality-middle high end speakers at a great price point right now.
4. The best part of the $250 upgrade is the tweeters. Seriously. The other speakers add 6 more tweeters! That's just ridiculous, and my tinnitus would not stand for that at all....
With these points in mind: Morel Tempo Ultra series speakers are worth your time & money if you are going with an amplifier, and maybe even if you are not!
I have completely removed every speaker I installed into my truck, and have replaced the hodge podge with Morels all the way around. Make no mistake, this is NOT a "plug and play" system, but I'm sure you can make it one if you wanted to. It is also not "budget" like the $250 system, but it also doesn't sound budget.
Fronts:
Morel Tempo Ultra 692 Component set: $299
Morel is a highly regarded speaker company. They have offerings from low end to very high end. The 692 set is what I would consider to be a understated middle-high end speaker set. While the Crutchfield fit program says that these will not fit in the front door space, I can assure you they do (albeit with little space left over) with Metra speaker adapter 82-8146. As you can see from the comparison pictures, the magnets are just friggen HUGE!


Here is the speaker completely filling the front door hole:
The tweeters are not too bright and have a very good range with excellent sound reproduction. I mounted them in the OEM dash spot (until I can come up with a better solution). The sound doesn't bounce around, and the tweeters actually sound better there than I though they would.

I installed the tweeters using mounts from
Car Speaker Adapters, who specialize in Toyota/Lexus adapters. I also soldered plugs to make them easy to remove.


This speaker set has very rich, deep bass that can go down to 50hz, and I would argue that you can run these without a subwoofer, while also having a great range tweeter that is not harsh. It LOVES power (130wRMS).
Rears:
Morel Tempo Ultra 602 Integra: $269
I purchased these from Woofers Etc because Crutchfield is out of stock, and I didn't need the adapters or harnesses, as I already had them on hand. Crutchfield's fit program does say these fit in the rear doors, and if you buy them from the crutch, you get all the adapters and whatnot. These speakers also love power (110wRMS) and can also be used down to 50hz, precluding the need for a sub (if you so desire to run without one). The speakers are incredibly well built with soldered in crossover resisters to protect the tweeters from lows and the woofer from highs.


The Kicker 43CSC674 is billed as a 6-3/4" speaker, while the Morel Tempo Ultra 602 Integra is billed as a 6-1/2" speaker. Looking at them side by side, the cone surface space on the Integra looks larger:
The magnet is DEFINITELY larger:
Installed:
So let's get down to it here. Almost $600 in speakers is not a "budget friendly" purchase. However, I spend a lot more time in my truck than I should because of my commute (purchase date was Dec 31 and as of today I am just under 17k miles), and really would have great (near SQ) sound quality powered cleanly, with the amp gains matched properly to the head unit. These speakers are a fantastic bang for the buck, and were worth every penny I paid for them, as compared to what I had in the truck before, and are millions of times better than the OEM speakers.
Right now my amplifier settings (Arc Audio 850.5 XDi) are set as follows:
Front high pass set to 90hz
Rear high pass set to 100hz
Subwoofer low pass set to 60hz
The settings for the speakers are temporary, as I have them set a little on the high side in order to properly (or responsibly) break the woofer drivers in. I will probably set them down to 70 in the future, and for the rear set the pass to "full" range, but will do so incrementally.
The crossovers are mounted under the driver's side rear seat:
Recommendations:
If you like full, rich sound with great punch bass, these are your speakers if you intend to power them with an amp. As I said, these speakers are so good with low end range, you could probably forgo using a subwoofer, which means instead of getting a 5 or 6 channel amp, you could go with a higher RMS 4 channel amp, but you would also be running new wire for everything. OEM wiring can handle up to 85wRMS, which is why I am using the 850.5 (85wRMS per channel @4ohm).