107 Vacuum system replacement

I have a 1973 450SL which basically runs great. It gets about 17 mpg on the highway. My only complaint is that it idles rough. If it's at operating temp. and I stop at a red light or stop sign, it will idle fine for about 3 seconds, then it will begin to idle progressively rougher. It the car is at operating temp and I turn it off for five or six minutes, it will idle very rough and sometimes die when I restart it. I attribute all of this, at least partly, to a leaky vacuum system. I know there are at least some leaks b/c the passenger door lock stopped working within the last year, as well as the heater (I have to open the hood to switch the heater on).

Does anyone have any experience with re-plumbing the vacuum system? What should I pay particular attention to? Does anyone have experience with a good aftermarket vacuum pump, or should I go with OEM?

Thanks for any comments.