I have not had the Mulberry springs fitted but I have now had 3 different sets of front springs fitted to the car. The first, ex-factory, had the ride height of the car too low and was replaced under warranty. Not only was the ride height of the car too low but the suspension was very harsh. The mechanic was convinced that the lower spring fitted was too strong and compressing the upper spring too much. When the springs were replaced the ride was acceptable but it seemed the car had excessive body roll in cornering. I then fitted the Suplex system.
I had been following the development of the Suplex Traditional Morgan Front suspension ‘Refinement System’ and as soon as I could lay my hands on a set I had it installed. The benefits have been described elsewhere by several people but it is worthwhile mentioning a couple of them again.
Firstly the upper spring system: It is a double spring system in which the outer main spring is adjustable for the weight and ride height of the car and the inner, ‘Rate Riser’ spring , does exactly what says and as the main spring is compressed it takes up on the ‘Rate Riser’ spring increasing the force required to compress the set. The benefit of this is a supple initial ride that gets stiffer as the spring is compressed.
The lower spring: Traditionally Morgan cars had a lower spring under compression. You can think of a compressed lower spring as contributing a pre-load to the upper spring that disappears as soon as it becomes unloaded. This was what caused the "nodding-dog" syndrome on some older Morgan cars and also caused an initial hard ride that softened as the lower spring became unloaded. This was the reverse of what is desirable.
The Suplex lower spring is set so that it is not under compression at static ride height. This means that it is not contributing to the initial rate of the upper spring, as it would be if it was under load. Also, importantly, it is very stiff. This limits the rise of the inside wheel in cornering and effectively works in combination with the rising rate spring on the outside wheel to reduce body roll in cornering. My car corners very well with little body roll.
For older cars the Suplex kit comes with a set of bearings that replace the old friction blade system. This is not needed on newer cars but can be used to replace old worn bearings and seals if necessary.
The Suplex Traditional Morgan Front suspension ‘Refinement System’ is optimised for road use with a set of Bilstein dampers that are made specifically for the system. I understand that there has been some work done on a competition system that would have much stiffer springs and an adjustable damper, but if that was of interest you would have to talk to Suplex about it. My understanding is that it would provide even less body roll in cornering and a faster initial turn in, but a harsher ride on public roads.
I'm not associated with Suplex in any way, I'm just a happy user.