I got over "liking" particular sounds many, many years ago as I listened to hundreds of LP's and CD's on millions of dollars of top end equipment and comparing that to live performances. Ultimately, your ear becomes trained to spot what is in common with them all, and that is what is actually in the recording, not modified or colored or altered compared to what actually is in the recording. I like reality. I like what is accurate. I like to hear what actually was recorded on the CD. Other people "like" screaming tweeters and bass that you can hear from a mile away as the car rattles all over. No thanks. I am listening to some music on my studio monitors right now.
Just give me what is on the CD. The setup I have installed does that pretty well. The 6x9's in the doors were an important contribution to that fact. There isn't a pair of component 6 1/2's out there that could do what the 6x9's do combined with the crossed over, timbre matched, and properly attenuated 3 1/2 coaxials in the dash - period. I've owned soooooo many 6 1/2's over the years.
So, what is the other side? I am talking about the physics of the 6x9, its benefits in general, and specifically 6x9's in the doors of the FJ.
Ultimately, there are other issues that need to be addressed, like physics for example. I mentioned proper crossovers, attenuation, resonances, dispersion, and timbre matching already. Unfortunately, there are multiple other issues that you cannot address listening to speakers in a showroom such as the overall reflectivity/absoption of the interior, the volume of the air space in the interior, whether any damping (sound absorbing) material is used around or behind the speakers, road noise, engine noise (always listen with the engine running because that's the way it's going to be most of the time), and so on. Fortunately, I was able to engineer my own system. It took me several attempts to get it right, but persistence pays off. So, the BEST bet (unless you want to engineer your own system like I did) is to go to a very good car audio shop and ask to hear some of their actual high end installations, not show room demos. They have trained ears, and they know what will work best in your FJ.
-FJ Florida-