It is impossible to tell you which make and year car to obtain a mirror from. I have removed many different type Electrochromatic mirrors from the exact same make and model car. Some had compatible mounts and others did not, yet they were all factory issue for the same car. You have to know what to look for or be able to test the mirror in your Z.
This page attempts to show you what to look for.

Due to the very high placement of the mirror mounting lug on the windshield, not all mirrors are able to adjust enough to be usable in the Zs. There are two requirements that a replacement mirror must have in order to work with the mirror adapter.

1. The mounting stem can NOT be centered on the mirror. It needs to be close to the top edge of the mirror. All of the mirrors in the top row of the photo below WILL work in the Z3 with the angled "Tall Guy" adapter.(all adapters are now the "Tall Guy" style) Notice that the stem is closer to the top edge of the mirror than the stems in the bottom row, none of which will work in the Zs.

The mounting lug on the mirror can NEVER be the low profile spring clip type (left side of photo above) that joins at the far end of the lug. All other lugs (right side of photo above) that attach to GM style dovetail buttons can work, IF they are on a compatible mirror with a non-center located stem.

ALL of the mirrors in the TOP row will work in the Zs.

NONE of the bottom row mirrors will work in the Zs.

The Gentex GNTX-177 is the ONLY Electrochromatic mirrors with a compass or compass and outside temperature that I have found that can be used in the Zs.

There are probably many more that will work, but I have not personally fond any yet.

• Electrochromatic with temperature only
• Electrochromatic with temperature and compass

#1 mirror
This is a Donnelly EC mirror that has it all... EC, compass, temperature and reading lights. It does NOT work in the Zs as the stem is located too close to the center of the mirrors back and it has the spring clip mount that forces the mirror up too high to be able to adjust so that you can see straight back.

#2 mirror
This is a Donnelly EC mirror with compass. It does NOT work in the Zs as the stem is located in the center of the mirrors back. This placement of the stem raises the mirror too high. It will not clear the header of the windshield.

#(not in photo above) mirror
This is a Donnelly EC mirror with compass. It does NOT work in the Zs. The stem is almost located in the correct location of the mirrors back, however it just misses being able to adjust so that you can see straight back.

#5 mirror
This is a Gentex GNTX-177 Electrochromatic mirror with a built in compass readout. It does work in the Z3 with the angled adapter.
The buttons read COMP - TEMP

#5 mirror
This is also a Gentex GNTX-177 Electrochromatic mirror with a built in compass and temperature readout. It also works in the Z3 with the angled adapter.
The buttons read COMP - MIRROR

#5 mirrors
The two mirrors above are identical except for the lower one having the outside temperature added. They both have the same number on the back, GNTX-177. The easy way to spot the difference is the labeling on the two buttons.

#6 mirror
This is a Donnelly mirror with EC ONLY. It does work even though it looks exactly like compass mirror #2 that does not work. The difference is the stem location on the back of this mirror. It is not located in the center like the #2 compass mirror, but is located very close to the top edge of the mirror. See the photo below

#2 and #6 mirrors
Here is a better comparison of the locations of the mounting stems.

The compass mirror's stem ( RED ARROWS) is not close enough to the top edge to allow the mirror to adjust once it is mounted. This mirror is a NO-GO.

The EC only mirror's stem (GREEN ARROWS) is very close to the top edge allowing the mirror to have enough adjustment to work in the Zs. This mirror is a GO.