I'm hoping someone might be able to share their experience with having Mac amps updated. I've heard of many folks sending amps and other vintage pieces off to Mac, Terry DeWick and others to be reworked, caps replaced, and some cosmetic improvements. I was lucky enough to have a set of MC60s, a MC240 and two C20 preamps handed to me. I have had them all in for the initial once over, warm up on a variac, and tube check, but that's it. That was nearly 8 months ago and they have all been in daily use since. The MC60s / C20 combo in particular sounds fantastic hooked to a set of Martin Logans and a linn Axis turntable. Half of me says, "if it ain't broke, don't fix it" and the other half thinks about want it could sound like. Any personal experiences you can share and maybe some idea on cost and time period you had to be without it would be appreciated. Did it make a night and day difference? Thanks!