I have read that some members had the H&R Sport springs/Koni Yellow Combo and did not like it, either too harsh, bouncy or ride height not good etc. etc.
I had mine installed last week and compared to the OEM Sport Suspension, which hopped around like crazy on bumps (read: Montreal street is really a war zone), this combo IMHO drives much smoother and tighter. No more bouncing around, oh by the way, I am still with the runflats. So even with the runflats it's smoother. The car now sits without any gaps between the tires and the fender (tires slightly inside the fenders at all corners).
The reason I decided to do suspension is that I occasionally track the car and on high speed curves, the car was rolling (leaning) too much. I did not pick the H&R Race setup, cos it would have been a killer on Montreal roads. I will be going to the track (HPDE) next weekend and will report back what I find.
SB, Terra, 6MT. Only a few mods here and there.....nothing extreme!