I'm quite certain only three changes to the body : 1) a special focus screen that outlined the data-imprint area, 2) a small mask in the film gate that prevented a corresponding section of film from being exposed to the 'taking' image and 3) the word 'Data' engraved next to the serial number on the top plate. Any standard F2 body/finder combination could be used with the MF-10/MF-11.

Sover Wong's website states 5,000 F2 Data units were produced, meaning one unit = F2 body with data back. (Sellers, so they can falsely justify a higher price, often say only 1,000 units were produced...or 500, or 100, or 10!) Sover doesn't state specifically how many of the 5,000 units had the MF-10 (standard 36 exp data back) vs. the MF-11 (250 exposure data back). Data bodies are often separated from their MF-10/MF11 Data backs. The Data bodies without the proper backs aren't worth much more than average F2 bodies. But the proper body and back set is rare for sure, especially if all components of the MF-10/11 are included. But not nearly as rare as the F2H (Highspeed), of which there were a whopping 500 units. Unlike the Data, the Highspeed has proprietary everything: titanium body, titanium motordrive, battery pack and battery charger. That's a bit more info than requested but intersting to note.