@vinny55 you bring up an excellent point on the Scott amplifiers.
We’ve seen example after example over the years of well-meaning techs going through a vintage component, and replacing the carbon composition resistors with modern, stable, reliable, tighter tolerance parts leaving the owner feeling utterly disappointed with what they wind up with. Fortunately, so many have come to the realization that despite all their shortcomings, for the owner of a vintage piece, in order to maintain its original character it’s best to use the same sort of parts they were built with.
As for modern audiophile components, unlike the guitar world, unless someone truly aims for that sort of vintage sound and feel, I don’t see any reason one would consider carbon composition resistors.
I’m less dogmatic in terms of brands of each type of resistor, as they obviously vary to a far smaller degree than moving from type to type. There’s a truly excellent thread in the "Tech Talk" section on this topic, though it focuses on folks experience with the nth degree in chasing the best of the best, and until one reaches that high a plane, they don’t need to look beyond the mainstream products offered by the major sellers. However, you may find it curious that excellent film resistors from the likes of Vishay, Dale, CTC, etc. can cost a few cents where carbon composition resistors could cost a buck or three.
There are a few notable people attached to each product or manufacturer of vintage gear. If I were you or your friend needing my vintage component gone over, I would seek out the forums dedicated to that particular product, as those individuals will surely show up there or get talked up by the devotees. As an aside, if you feel at all comfortable working around these things, I encourage you to become your own tech. That's the way you really maximize what you have, as you will become intimately knowledgeable about it by the combination of finding a group of people who also are on the journey with the component and eager to share their experiences and perspectives and lessons learned, and actually putting your head down and working through the piece yourself, not to mention also being the cheapest way