Trying to get this thread back on track....
The springs are but one part of the rear suspension equation. The shocks are equally important.
I spent a lot of time and effort back in the 2000s trying to improve the suspension on the then new Triumph Bonneville and came to the conclusion that they must work in harmony together, be appropriate for the load and use.
A multi link system at least ties the position of everything better than the leaf springs. Then the spring characteristics and damper capacity need to be matched to the load and use. So what works with a driver like Henry Williams on the track will not be ideal on the road with two large people and a load of luggage.
The BIG advantage of the any multi link system is that it uses coil over units and provided one is willing to spend the money the spring and shock can be set up for the driver and the main use. It is also relatively easy to change the two parts.
Mind you, the Plus 8 already has quite a sophisticated multi link rear suspension...comfortable and effective...
