Anti roll bars
Always a question for debate. Let's first see what the factory did with these simple devices.
Up to 1974 when rubber bumpers were introduced, only a front anti roll bar (arb) was fitted. These cars are on so-called chrome bumpers ride height. If you have driven such a car you will notice that it has typical oversteer reaction (the rear steps out). The car feels pretty solid on the road; it has predictable reactions that befit a sportscar. The roadster had something like 5/8" front arb, the gt had 3/4". Front only.
After 1974 the rubber bumpers were introduced and ride height got a whole inch higher. So the center of gravity - that causes the rolling motion - is quite a bit higher; almost an inch as well. First MG did nothing. The result? The car was all over the place and drove like a pudding.
A nice example was shown on Discovery Channel, where a chrome bumper V8 was tested on a racetrack. The c/b V8 uses the r/b front crossmember to clear the sump of the V8. Therefore it has a higher ride height than the normal c/b cars. Nothing was done to counter the negative effects, so the car rolled a lot.
MG were not mad, so after 1976 a rear arb was fitted. This countered the roll, and got the familiar oversteer reaction.
However, the rear arb can cause snap oversteer when you push the throttle a bit too happily. To get back to the original response, the best is therefore to lower the car to the original ride height, and remove the rear arb. This is what I have done, and the car handles very well. Stiffer springs front, thicker front arb, no rear arb, and neg camber wishbone arms. She runs like on rails.
If you want to stick to the "inch higher" height, maybe to counter the ever increasing number of speed bumps, it is a good idea to fit the rear arb. Then rear 5/8", front 7/8". I have driven with this setup and it is pretty good.