I was a member of one modification team (there were two) installing outboard pylons to F3’s. No structural Mods were needed and rods and swivels were installed and rigged as per GR’s. We must’ve done about a dozen or so.
The new wing kit was installed for fitting ECM gear to aircraft going to Gioai del Colle (Spelling!) during the mid 90’s.
The whole gear weighed almost a half ton and was a typical OEM disaster – making the jets fly at full throttle to push through the induced drag. Reducing engine life and increasing Airframe fatigue too. The cabs were limited to low G turns too IIRC.
Can’t say how long the ECM lasted (But I’m sure it wasn’t long) and I assume the Wing Pylons were removed but probably not the internal swivel gear.