Which diff should i use?

[russiane30]

get a 3.25 i bought one from BOBY and i love it on a highway u top out about 145 148 and i raced with my friends e36m3 he was in a 4th and i was in 5th and it looked like he was standing still. its verru torque

[sharky]

3:25 is a good multi use ratio.

[1990m3]

search youtube, there are a lot of swap car vids and the diffs are often listed in the description.

e36 m3 diffs have different moutning points and will not work in an e30.

[Strickly German]

Wats up i got a e30 im puttin a s50 in complete motor trans i have the diff also but i was told to use a 3.25 ive been searching and looking for vids but can really get an answer. Im lookin to do good numbers on the highway bassically w/e she can push and im not looking to get launched on off the line.. i was told a 3.46 is good but not sure on wat it gives u off the line and in top gear.. and secondly why cant i use the 95 e36 m3 diff isnt it a 3.46 also?