Looking to get a longer diff on my e30 m3

[m3j0n]

You have a ton of options.

Any Z3M diff will bolt right up, and get you very close to the gearing of a Z3M. Because the E30 tire diameter is smaller than a Z3M's, the effective ratio will be slightly higher.

So, a 3.15 or 3.23 from a Z3M will work. An E28 3.25 or 3.46 LSD will also work with the finned diff cover. If you want a nice low diff ratio, you can get a 2.93 from a 325e.

is a z3M diff any different from a standard e36 diff, for example one from an e36 m3? Which year z3M had a 3.15 vs 3,23?

[FredK]

You have a ton of options.

Any Z3M diff will bolt right up, and get you very close to the gearing of a Z3M. Because the E30 tire diameter is smaller than a Z3M's, the effective ratio will be slightly higher.

So, a 3.15 or 3.23 from a Z3M will work. An E28 3.25 or 3.46 LSD will also work with the finned diff cover. If you want a nice low diff ratio, you can get a 2.93 from a 325e.

[m3j0n]

what are my options if I want to stick with a factory LSD that fits in an e30 m3 and can accept an mcoupe finned diff cover?
my factory diff is a 4.10 and its way too short with my 95 m3 s50/zf swap. What LSD ratios were offered from the factory that I should consider? Thanks!