Difference between M3 front subframe and regular E30s?

[nrubenstein]

I'm about to send a couple subframes off to TinyT for rear sump conversion. What is the difference between the M3 subframe and others, other than the lack of parts commonality? Until I looked on RealOEM, I hadn't even realized that there was a difference.

[Farbin Kaiber]

I know the early 318i's have a engine dampener (shock absorber) mount on the passenger side. I'm pretty sure they are all the same otherwise.

[Jean]

^ probably just that. But I am curious to know if there is another difference.

[reelizmpro]

I know the early 318i's have a engine dampener (shock absorber) mount on the passenger side. I'm pretty sure they are all the same otherwise.

You know I've seen this on a late 325iS too if we are talking about the same thing. I don't know if it was part of the subframe or just a transmission brace for automatics.

Anyway, the M3's had extra reinforcement under the engine mount ears. I have seen some M3's with and some without. One possibility is that all M3's originally came with the reinforced ears but due to the buzzy S14 cracking the ears, people replaced the subframe with standard E30 ones. M3's really need a thicker subframe mounting ear (Turner sells reinforcement plates) to prevent cracking, not just a gusset from underneath.