To those experimenting with different resistor types, we tried seven or eight on our BentAudio Mu stepups.
In our system, to our ears, Vishays and all other film resistors had one audible flaw. Because of their high surface area:volume ratio, very high frequencies were largely uncontrolled. Even went we took resistor values low enough to audibly attenuate middle highs and upper mids, true high frequency response remained excessive.
We preferred carbon resistors, like Kiwame's, for their even and balanced effect at all frequencies. YMMV of course.