Awesome thank you.In my opinion, most people should be happy with a high quality 6.5" but, I have loved and had many SQ stereo systems for 35+ years now & I still am passionate about them! My main goal is for the 4 main seating positions to have a great SQ experience, soundstage at concert volume levels.
In my opinion the hardest thing to achieve in a car system is the midbass from 70hz to about 250hz. This is because of the size & geometry of a vehicle. (In case you are wondering, the easiest thing is to achieve in a car system is subbass 30hz to 60hz).
To answer your question, my 1st system in my 2001 LX had Focal 165KRX3 (3 way components 6.5", 3" & 1") in the front doors & Focal ES100k as the center channel. Plenty loud but, no matter what I did, I couldn't tame the Focal's to make them sound musical.
I slowly upgraded in multiple steps to AudioFrog GB60, GB25, GB10 in the doors & GB40, GB10 as the center channel. This is a very good sound system that should satisfy most anyone.
I still wasn't getting the midbass that I desired. So then I also installed some 5.25" mini subs in both front footwells and a JBL Fuse to compliment the AudioFrog system above. I could get a very good sound curve but, I wasn't getting the concert volume levels because of having to do too much EQ work.
The reason for the 8" in the front doors is to help reinforce the dip that I had at around 65hz so that I wouldn't have to do so much EQ work and overload the other speakers.
The current system sounds great so far, gets decently loud and I am glad that I done it!
P.S. The rest of the system that I have no complaints about & have never felt the need to change:
Kenwood 9903s
Two AudioFrog GB10D2
Focal ES165k in the rear doors
Focal ES100k behind the 3rd row seats
JBL MS8 Logic7 processor/DSP
Three Arc Audio xDI 1200.6 amps
Two rear mounted batteries
250a Alternator
I loved those es165k speakers when I did my tour of auditions a few years ago. I still haven't heard any of the audiofrogs, but I've listened to plenty of Andy's trainings and such.
If you're ever in the Denver area I'd love to hear the setup!