If the motor actually sounds like it's going to die, not just that it dips really low, then try slipping the clutch a bit more and revving a little higher when you take off. That'll keep it from stalling - you may just have a bad throttle cable or something, I think that's what's causing some troubles with my car.
I really don't know if a lot of other BMWs do this, but most of the people I've talked to around here with Etas have slightly bouncy idles. I think it may just be the nature of the interference engine. Unless it's shooting up or down 500rpm, I don't think it's anything to worry about. If it's getting on your nerves, and you haven't done so already, try replacing the ICV and/or spark plugs, wires, injectors etc. Even if that's not causing the problem, it won't hurt anything.
It's also a twenty-four-year-old car.
That right there can explain a lot.