I heard it was the other way 'round: Sarroni was/is a contract-builder for Colnago, but that's the internet for ya! I do know that Giuseppe Sarroni was a world-class racer and had close ties to Ernesto Colnago, and I have a Celo Europa that's essentially a Colnago with another decal set from about 1983 that I was told was built by Sarroni. I believe that, like Ernesto, he doesn't actually do any torch work, but has skilled builders either in his own facility or, more likely, in a bunch of little workshops scattered around who build the frames that he puts his name (or Colnago's name) on. I expect that a Saronni will show a very close resemblance to a Colnago of the same vintage, and will ride like one, too...but that's all the help I can offer.