[analog31]

I recommend measuring the noise. Systems guru Phil Hobbs said that you should know where every dB of noise comes from in your design. Of course a dB could be a little or a lot in your application, but the point is that you should perform a noise budget and then test your assumptions.

It's not necessarily easy, but recommended if possible. I was doing it with DIY equipment, so I don't claim traceable results.

In one case, I literally measured the noise of some resistors, and within the parameters of what I cared about, I found no measurable difference between metal film and carbon film. I was passing no DC current through the resistor. Some sources of "excess noise" are proportionate to DC current and can be corrected by appropriate filtering.