LSD

I fitted a LSD diff, from a Toyota supra turbo, to my Stag years ago. You do notice a difference on the drive out of the corner, and if you do lose traction then it’s a sort of weird feelings it grips or both will spin. My LSD though is the torsion type not electronic type put in new cars nowadays.

They are becoming harder and more expensive to find, plus you’ll have to modify or update the driveshafts to fit. It not a straight forward swap. Unless a company does make upgraded Triumph stag limited slip differential gears to fit into the original diff housing.

Is it worth it, possibly for a standard sort of stag but if you have modified the car and it has considerably more torque  than standard then yes it would be a good idea to strengthen the whole drive train.

I have never tried one, I work on the basis that if I am dumping lots of power into a standard diff the wheelspin will unload the diff and prevent breakage.
A guy in the local TR group fitted one to his TR6 and all it did was make his understeer worse and the final straw was when he accelerated hard with one wheel on loose gravel leaving a club night at a country pub. The wheel that gripped the tarmac ripped the entire hub from the trailing arm.
He was lucky it didn't cause much body damage due to the low speed at which it occurred, and to be fair I reckon the mounting studs were probably shagged as well, but it was the final straw that lead to him selling the car.