would a 84 318 LSD fit my 91 318?

[SlammedE30]

Tearing apart and rebuilding a diff is a PITA. You definately have to know what you are doing (shims, etc) I don't see the huge deal with running a 3.91 if it's only $135. Run it til you find a good 4.10 That's my advice,
-Ted

[nickmpower]

maybe if i had a bmw shop do it?

[SlammedE30]

If you are going to have anyone take apart and reassemble a diff, it should be a diff shop. They know what they are doing more than anyone.
-Ted