I'm into modernizing my bikes as well. My 753 framed Condor, still awaiting it's vintage status since it's early 90's, came with an Athena drive train and Chorus brakes and levers. I finally scored some Athena brakes and a set of Athena 8 speed brifters so it will be receiving those period correct options very soon. I would also like to come to terms with the basically unridden original Hope hubbed Ambrosio Crono tubular wheel set that came on it. I just don't like riding tubs and sweating the flat issue for a non racing environment.

My Dawes maintains it's original 8 speed Shimano drive train but I did put my trusty Brooks on it since it sees most of my miles.

Everything else I have is a combination of modern drive components, or at least newer than the original bike came with, and the classic steel frame. The frame set only approach makes this a lot easier to do.

If ever I stumble into a deal on a classic DeRossa, Merkx, Cinelli, 'nago, etc that happened to have an intact pantographed gruppo I would probably have some serious soul searching to do before I made any changes to it.