Last year I put the 8lb UUC Flywheel w/M5 clutch in my 525i, I love it. I get some gear chatter with the AC on when I'm waiting at a light, but otherwise I'm happy.
The best pro is that the engine winds down faster, so it's easier to shift and match revs. That and it was cheaper than a dual-mass flywheel!
Biggest con is that you have to get used to the lighter mass, because it is quite significant. It's quite a bit easier to stall out with this setup, but like anything else, you get used to it after a while.
Some people aren't comfortable with this setup, the tradeoffs aren't worth it I suppose. I've been quite happy with my it, and from what I read, my gear rattle is mostly due to slop in my transmission. The problem is hit and miss, a lot of the E36 guys only see it on a limited basis, and sometimes not at all. I hope to be able to replace the motor/transmission this year and then it won't be a problem.
Can't comment on an M30 install, but I expect the results to be similar. Whether or not you like it? Guess you won't know until you try