It goes something like this. Many early Ferrari owners would bring their cars back after a few seasons reporting sluggishness, erratic running, backfires etc... The mechanics knew (almost too well) what to do. The customer would leave the car with them for a few days. The mechanics would take the cars out and flog the hell out of them for 50 miles or so; going the gears, pushing the redline, hard downshifting etc... Essentially, they were blowing the built up carbon and junk out of the engine and carbs. The owners, not privy to a racetrack, had no place to wind them out and were pretty much putting around, clogging the engines. They would get the cars back a few days later and be in awe of the mechanic's skill at "tuning" their Ferraris.
Early Porches and 911s usually didn't like to run under 3,000 RPM, the amazing 4 cam engines were never supposed to be run under 5,000RPM
(Those 4 cams were sexy as hell!)
So that's what an Italian tune up is. My bike only had 144 miles a year put on it and I think it could use a good rowing through the gears.
Jeff