I've had the fk coilovers for just over 30k kilometers. They weren't bad overall. Decent stability and reasonable ride comfort for the "stance" they delivered. Bear in mind I used Koni rear shocks and not the kit supplied shocks at the rear. I've returned to standard Gabriel shocks upfront and retaining the Koni at the rear with standard springs all around. Reason for this is it started feeling mellow and I needed to return to std height for ground clearance.
If you want to tinker with ride height on a budget and you're not concerned about years of service, go for it . If you want quality at a higher price, go for a Koni , Bilstein - H & R spring and shock combo for durability. Ultimately any big brand coil over system from the likes like KW and Bilstein at a premium.
As mentioned above first refresh components that need replacement before anything else. I had to replace top mounts when returning to std . Try and use quality components and not cheapies as it does make a huge difference in the long run.
