Maybe there also is a question to whether what was "stock" components on an older bike was the best it could be. It really depends on how you look at a particualr bike. My Vitus Carbone came to me with Shimano 7400 series DA components. Certainly one of the best performing component groups from the mid 80's but the components were a bit "tired" and I concluded that it is justified to turn the Vitus Carbone into an "all French" bike, instead of trying to revive/replace the old DA components, which was gonna cost me an arm and a leg anyway (Ever priced NOS or mint/used DA 7400 brake levers lately?? Yikes!!).I believe that with a bike like the Vitus Carbone that just screams "French" the move over to an all french gruppo makes enough sense despite the lower performance I would get from them compared to the original DA group. Anyway, I never really felt that these very French brands looked quite 100% with Japanese components even back in the 80's when they were sold. I still will put in the newes clip-on pedals and tubular tires I could on the bike for the sake of safety though, so I guess you can call me a 95% purist??

Chombi
84 Peugeot PSV
85(?) Vitus Carbone Plus 7