The micro fusion bottom bracket, and frames without cs bridge, started in 86-87 with the "pros".

I have a '85 "pro" with the cs bridge. I have never owned a Primato…but as Aaron said they are highly desirable.

I do own an EL-OS bike though…Chesini Innovation…and the ride is quite nice.

The later TSX bikes were Nuovo Classicos….and this nameplate carries on today, albeit with different tubing.

I'm not familiar with the Diamant (?)…but…the Diamante chainstays are one of the features that give the 80's De Rosa it's legendary, and well deserved, reputation.

Later Primatos (Neo-) were built with Dedacciai Zero Uno, I believe…which is not as "advanced" a steel as EL-OS.

There were also late production original Primatos built with Genius…this is the one I want…and frankly, I will sell my SLX Pro when I finally find one.

-Mark in St. Louis