Upgrading central speaker (in a dashboard) (PremiumSound)

[Zibi]

I Salute all S-Max owners! It's my first post.
I've got 2012 S-max with so called "first generation" player and a slightly upgraded speaker system, with a fifth speaker in a dashboard, (where most cars have a "secret box") and a sub under a driver's seat.
Recently upgraded the front pair of tweeters (at a side of the dashboard). I've chosen JBL; it was as easy as Lego Technic for big boys. What a difference it makes! My jaw dropped somewhere between the pedals and i still can't find it... I can describe that process, if someone is interested.
Now i am pretty happy with the sound system in general -- i wish my home stereo would play that good!
There's just one detail left:
For many years now, i drive to work my old trusty V70 with a central speaker in a dashboard and Dolby Pro Logic. I learned to appreciate the magic of strong front, the clear vocals, saxophone solos, clear speech in podcasts. I understand it is very much due to Dolby PL magic; but even if i switch do "plain 3ch mode" it still blows my socks off.
This strong and clear front is what i still miss in my wife's S-max. Now, when i upgraded the front (side) tweeters, it plays amazing. But the central speaker almost disappeared. The fader in a Sound section of my player doesn't let me increase a volume of that speaker. It still has the original tweeter, which is a ***** joke, sounds like through a blanket. So i would like to upgrade the speaker(s) itself. I understand under a grill there's a place for one tweeter, identical to other four, and one round speaker, probably like 4" or 13 cm. 

Now, i have a couple of questions. Will appreciate if somebody may enlighten me:
-- how to get access to the front central speaker (drivers)? Is it possible to lift the grill -- how exactly? Or would i have to dismount the whole dashboard (like it is with door panels)?
-- does someone know how the central speaker is wired? Does it "steal" part of a signal from "normal" front outputs, or does it have it's own channel in a player unit? If the latter, is there a way to "secretly" access the settings of DSP? Or else...?
-- I will appreciate any information about the player unit, like on a picture

Thank you in advance,
ZIBI 

 

[Zibi]