Ciao Davide,
the tweeters are only accessable from under the dashboard. Sorry.
But if you want to upgrade your system anyway, leave the OEM-Tweeters where they are and put new ones where you like it. (perhaps mirror triangle)
If your door already has the fixure for speakers, there will fit 6" Speakers with a mounting depth of approx. 50mm.
Check out these (similar version should be avalable in Italy):
...at least the dimensions of this set will give you an idea...
The tweeters are only accessible from underneath and require the dashboard to be moved back a couple of inches. I’ve done it a few times, not a nice way to spend half a day plus needs quite a selection of tools.
I don’t have a complete guide, just work your way forward from the cup holder between the seats.
20cm in the doors would be a hard challenge...if you want to take it...
Check out the max diameter of the speaker grill. You might need to mount the 8"-speakers from outside and you might also need appropriate covers.
From my point of view, you should invest in a good pair of 6"-speakers and good damping of the doors. This way you at least don't have to cut the doorpanels.
Ok but all the real good 6'' speakers are more deep than 50mm... Am i wrong?
Might be.
But a 8" has a even higher depth.
The only way to find out if a speaker fits, is to remove the Doorpanel and to measure the depth. (or anybody already knows here)
originally installed
https://www.lzparts.de/focal-m…ive-version-4-0-ifr-165-4