the spax springs are pretty harsh, even with my dampers on the softest setting its pretty harsh.
You wont get a kit that performs well and handles well, imo.
The spax 60mm springs are harsh mainly because they have to be, due to how much the lower the car - youll find that with any kit that lowers that much.
The best thing to do is go for coilovers, the likes of H&Rs have seperate helper springs to help smooth the ride out a fair bit.