I'm currently putting together a Vox "AC15" (top boost and normal channel) using JMI-style construction ( repro chassis, tag boards, repro cabinet, etc.) I elected to use carbon composition because if it works and sounds good, why not make it look the part as well? I'll be using modern best-practices such as star-grounding and sheilded wire to keep noise down and as long as they don't cause a problem I'll leave the CC resistors in. If I'm not building something vintage spec, I use carbon film for asthectic and possibly sonic reasons. I've built some nice and quiet amps with them, I'm not sure that going to metal film or wirewound resistors just due to number on the spec sheet translates to any actual improvement in audio performance.