Tein Flex, and an older Cusco kit. Actually, it's funny for all the diffrent coil over brands there really are only a few "fundamental" differences. mostly valving and spring rate are diffrent between brand. of course there are some bespoke models.

Some use inserts, and some are non-rebuild able at that. In those cases I replace the inserts with rebuildable ones I spec out. I tend to prefer a much stiffer damping for a given spring rate then most factory kits.. but most when rebuilt can be "fixed" most dampers marketed as "rebuildable" are what is considered "driver serviceable" and they tend to be the higher end units since making all the parts and tuning info available to every customer is a monumental task. but oil seals wipers and valve stacks are pretty universal or at least easy enough to reverse engineer. but I'll be honest, most rebuilds are rebuilt to kit specs since it's for service work.. I prefer to use a slightly more expensive synthetic Multi-viscosity shock oil based on the application, it tends to be more stable in our intense heat. and you can actually use a stiffer damping with a lower "cold" weight. so when pushed hard the dampers don't "go away".

For shock applications, some times I find it's best to replace the whole threaded body and transfer spring seats etc with something like an afco since it's not much more and I can spec out digressive/progressive/ or linear valving based on what the customer wants the car to do.

so after taking the long way around, the answer is most anything.