[Dave Turner]

We used the Flex Form springs for 4 seasons in a 3450 lb Stock Mustang. Replaced them with Calvert product when both sides started to split(delaminate?) between the diff and the rear mount. The manufacturer suspected that we missed the spring rate target when they were ordered.

I didn't notice significant change in track results and expect durability to be superior. It appears that the split monoleaf spring allows greater separation based upon before & after pics.

The fiberglass springs rode smoother on sketchy return roads, I must say that.