At 5K on Conti SC2 I did a driving school and autocrossed the car. Destroyed the rears- shoulders had no rubber left. Fronts had maybe 10% left. The local Porsche club guys recommended Kumho Ecsta 700 Competition tires. I have ridden on them for two months and autocrossed last weekend. Expect 7-8000K max from them, but they are quiet (quietest performance tire on grooved pavement, ride very well, but more importantly are sticky and progressive during hard cornering. Great tire!

 

I have got the conti's, have 13000 miles and they still look pretty good. I don't track but do enjoy the curves when I can.