I am considering using the mz3 finned diff cover on my 90 325i to reduce temps and maybe prolong clutch life. Its a well known upgrade.Has anyone actually seen lower temps utilizing a finned cover?....tia

Yes. That said, do you know that your temps are too high? ;)

for the price it was a no quetion move on my part. replaces a warn out diff bushing and the extra cooling is there.

Agreed...it's an obvious upgrade, especially for the E30 guys. As for the question of whether it works, I think BMW answered that one for you by bothering to design a new part of the MZ's.

......Im not sure of my current temps. I instlld an e 30 M3 4.10 diff this season and not knowing its history or mileage I figure the newer finned cover would only help. This used diff moans and groans a bit but its hard to tell how much of my noise is the poly bushes in rta and subframe. Im able to pick up a used (55k) mz 3 cover so I thought the harder bushing and finns would be an improvement over my current set up. Its just that I had "heard" temps w/ the newer cover did not change much......I found that hard to believe, so I thought Id run it by you guys...