The matiz mirror works great on S1s and early S2s. - if the ball-and-socket joint is on the back of the mirror it should work fine!
later cars have the ball and socket joint on the top of the mirror - i've no idea what works with that one - sorry!
your best bet is probably to do what i did - slide your mirror off its mounting, then take it to a scrappy, and try to find something smaller that uses the same mounting. - i couldn't find anything at all that used the same mount as mine, so i searched for something with the same size of balljoint, and broke the mirror there. - give it a try!
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