Originally Posted by Ryan @ RJM

Wigjiggy, the current Rev 3 series definitely has a large number of improvements over the older Rev1/Rev2 models. The main improvements are in ease of installation with the Rev3 coming as a fully built unit, where Rev1/Rev2 came in pieces and the pedal arm, bushings, spring and cross pin had to be installed in stages onto the firewall under the dash. The Rev3's are about half the time to install and tune. As well they have greater adjustment capability and a better AFP adjustment system with a built in indicator showing the setup point in 25% increments. In addition to the HD clevis system which is also easier and faster to install. Finally the upper switch mount adjusts in seconds with just a single tool. This is critical as the upper switch needs to be adjusted every time the AFP or clutch rod adjustments are made saving additional time and frustration during the tuning process. Gen3 is also directly compatible with the Tilton Gen2 HD Master Cylinder system where the Rev1/Rev2 units are not.
Hope that helps explain the massive differences that happened between the Rev2 and Rev3 series. They don't actually share a single part in common besides maybe the bolts used in assembly. Everything else was new from the base plate up or updated in some way.