I have been in contact with Quaife, and they could make a small production of differentials for the 172. They would like to have 20-25 orders, but less could do.
I am now just checking if enough people would be interested. If you are, e-mail me at htaipale@abo.fi, or just post here.
If you know any other producers that already has a good differential for the 172, please let me know.
I dont know the price just yet, but for other car makes it costs about 1000 euros/dollars.