Ah, yes; "local modifications"!
I had the dubious honour of doing the "intro" course when somebody decided to "upgrade" the NEW "Fire Support Vehicle" version of the much-abused M-113 in Oz service.
The first version had been to slap a turret from an obsolete Saladin Armored car, on TOP of a 113 carrier and call it "the Beast". It actually worked, but it was too heavy to "swim", except in a downwards direction. There were still a few floating, (or not, as the case may be), around in the late 1970's.
Some years later, well after the Brits fielded the "Scorpion" series of light AFVs, some bozo got the urge again; thus the 76mm gun turret of the "new" Scorpion series, grafted onto the unfortunate M-113. As Bullwinkle would say; "This time, fer sure!"
Yes, it was lighter (just) and a bit more "modern" inside, but, as, at the time, Oz armour MGs were Brownings or nothing, there was a lot of "creativity" involved in grafting a .30-cal browning into the mount designed for the MaG-58 / L7.
There was also a great deal of paranoia about leaping into the turret and landing a size eleven on the "Tritium" sight system, which, if broken, required the vehicle be evacuated post-haste; radio-active gas and all that.
The thing was still too top-heavy to swim and was eventually quietly and unceremoniously "disappeared". "Tanks" on the cheap are generally NOT a good idea.