Hi there everyone - I'm new here, so please excuse me if I break any local
protocols!

I have a late 90's Ford Scorpio, and will be looking to upgrade the audio
in the near future.

I'm happy so far with the information I've found on a replacement head unit
and fascia to adapt from the current 1.8DIN aperture. I'm also happy with
the replacement for the front door speakers (once I've taken the door trim
apart to establish the size).

However, the rear speakers are currently tweeters plus midrange. I don't
want to change the look of the rear speaker enclosures, so intend to
replace the drivers within the casing already present in the car.

First question. All the speakers I look at on various websites are dual
cone - they have midrange-bass cone with a tweeter sitting in the middle. I
would have thought that I'd want them without the tweeter cone attached,
since I am fitting separate tweeters. Is there such a thing? If not, will
the crossover effectively make the integral tweeter cone obsolete, causing
the speaker to behave more like a midrange unit?

Second question. I'm used to seeing car speakers supplied with a removable
grill, so you can fit them as a new fitting with the supplied grill, or
replace existing speakers of the same size and just not use the grill. All
the tweeters I look at seem to be encased in a plastic housing, with no
indication of whether the tweeter itself comes out of this casing to
replace an existing installation. Is it possible to remove them from the
plastic casing?

Thanks in advance for your help.