As Your question has not been answered I will attempt to do so.
Basicly the Mulfab unit is a 140in/lb spring with a thrust bearing. The spring has been shortened the same thickness as the thrust bearing to keep the "ride height" as designed.
The Suplex Kit is an engineered suspension system designed for a more compliant ride, on rough roads. It utilizes a 100in/lb spring, as well as a progressive spring installed above the stub axle which comes into play on large bumps. It also has a threaded upper spring mount that is adjustable (for ride height) according to weight.
The two are "apples & Oranges". They do different jobs for different conditions, and different driving styles.
