I used a program named Pokemon Stadium Editor. It lets you see the opponent's teams to edit them in game, alongside other things. But they also show the opponent's teams fully, including IVs and EVs they might have, as well as PPups.
Using this info, I used PKHeX to make exact copies of Mewtwo from Stadium's "Vs Mewtwo" mode, and decided to share with you guys!
There are two files, one is Mewtwo from Vs Mewtwo's R1 fight, and the other is the super overpowered and busted R2 Mewtwo. They should be exact copies of Stadium's vs Mewtwo, so now you guys get to see their stats and crush the games with Pokemon Stadium 1's final bosses!
Fittingly, I put the OT "STADIUM".