I had Koni coilover installed about 2 months ago. Something to be aware of is they will "settle" a bit after installation, so you may well need to take the car back to the shop (or adjust them yourself) a few weeks after the installation. Some guys set the adjustment up as "8 threads from the top", but the better way is to park your car on a level surface and measure from the ground to the fender lip and adjust the coilovers for the heigth you want (whatever that may be). I set mine up for a 1" drop in the rear and the front so the car appears level. Stock with just 2,000 miles on the car my front end was much higher than the rear which looked hideous to me.
I have heard nothing but good about the K1 coilovers, You are going to like them!