Looking to get one or the other for my F80 M3. Ruled out the Dinan springs at the moment otherwise I would jump on these. Spoke to an engineer directly at Dinan that stated M4 springs would finish development and be ready for shipment in roughly two months give or take, and probably two more months on top of that for the M3 springs. They currently have an M4 in the shop but not an M3.
So for now, I'm looking at the H&R Sport springs vs the KW sleeve kit. Between these two springs from what we know which are more similar to OEM in terms of design and spring rate? Looking for minimal drop in height, and minimal increase in spring rates. In other words, which have a more similar design to the OEM springs?