I know this topic has been discussed already intensively. However, 2 videos I put on youtube (Morgan roadster 3.7 rear suspension), which might still be of interest.
The first video I made with my Morgan roadster 3.7 with one anti-tramp bar:
http://youtu.be/otP5xU8qvYY
Some 2000km later I asked my Morgan expert to improve the rear suspension with 2 anti-tramp bars, a Panhard rod and AVO dampers (3 klicks r/f) and here is the result:
http://youtu.be/yaVDqJEEKR8
The difference in driving the car under sportive conditions is as already described very significant.

Axel.