Quick update after a long time!
Due to some medical emergencies in the family, we've postponed selling off the Ritz (I was going to take out the sony 4 ch amp from the ritz and plonk it into the 124, and change the ritz for a grand i10/xcent which would come with a factory fitted sound system. Wouldn't have upgraded ICE on that right away).
As such, the amp will be put into the 124 at a later stage.
Until then, I have upgraded the rear fills to Infinity Primus PR6502 coaxs. They are sensitive (which is a good thing as I'm powering them from the HU for now), and definitely make a large difference to the sound. Not as bright as JBLs. Quite warm, actually. The only sore point is poor low frequencies, but that can be expected from a 6 inch coax. Can't match 6x9's or a small sub of course!
For the fronts - When I opened up the grilles on the dash, I found enclosures that were larger than 4" to my surprise. I believe they're a custom Mercedes size which is around 4 3/4". Needless to say, nothing except original rainbows designed for the 124 would go into those :(
Used a ring to accomodate 4 inchers as were done before. I finally pulled out the bostons which I wasn't fond of!
Auditioned JBL CS 4 and Blaupunkt GTX 402 coaxials. I expected the JBLs to be brighter and the Blaupunkts to have their signature laid back sound, but was in for a surprise!
The JBLs were lower on sensitivity and sounded a little laid back for a critical front installation where they were supposed to provide high frequencies and soundstange imaging. The Blaupunkts sounded more "in front", but not overly bright. They also take better to fullrange input and don't strain when the bass kicks in (under the limitations of a 4" cone ofc).
Went for the Blaupunkts.
Although the system sounds a lot more complete now, it does lack a little bass (which I am anyway okay with. Resigned to it since I decided to omit the sub and due to the fact that my car can't take 6x9s at the rear or 6" comps at the front).
What is weird is, with the same fullrange input from the HU, fader slightly to the rear, and a little EQ tuning, the fronts sound clearer than the rears! The rears are warmer and handle mid-bass better, but the frequencies don't seem to be seperated enough.
I'm assuming adding the amp will enable a clearer signal to the speakers and give me more clarity. It is a little muddy for my tastes of as now (if I sit in the rear).
I drive 90% of the time, especially in this car, and the fronts seem to give me pretty good imaging given the limited budget components and the size/installation limitations. I guess the placement of the fronts helps - the 124 directs them upwards towards the windshield, and reflection from the glass tends to provide a decent soundstage. I'm sure audiophiles will think I'm crazy, but it works for me!
The other issue with this car is that the rears are placed similarly - on the rear tray, facing upwards. Add to it the sheer length of the car, and you can never achieve wholesome sound everywhere. No matter how you tune the fader, the sound comes from one end. For example, if I'm sitting in the front, the sound is primarily from the front (which is good because it sounds natural and agrees with the soundstage). But the bass, which is anyway low, doesn't reach me well enough from the back. Push the fader to the rear and it sounds like there's nothing much in the front.
Same story when you sit in the rear. Overall sound is from the rear. Fading to the front just makes it get lost in space, and requires you to crank up the volume.
By far, this is the most difficult car I've ever tried to get decent sound in
Will keep posting as I add on. Next steps, when circumstances permit, is to add in the amp, HPF the fronts, and add a bluetooth adapter.