if I were so purchase a set of the solid top mounts from balance motorsport would these fit and work replacing my bravo top mounts on my kw variant 2 coilovers?

I don't know. They were originally designed to be used for the GAZ Gold Coilovers so you will need to check the sizes of the shaft and how the spring platform locates underneath the top mount. The GAZ ones were completely different from standard FIAT ones.