I personally don’t have either but I would suggest the K Sport. I’ve driven a few 240’s with the slide kontrol coilovers. They seem to be a good quality good handling coilover. I don’t know if you intend to drift/race your car or just drive it. If you intend to drift/race your car spend the little extra and get the slide kontrol.
Get them here. Best price for them.
http://shop.hybridynamics.com/index.asp?PageAction=VIEWPROD&ProdID=34
http://shop.hybridynamics.com/index.asp?PageAction=VIEWPROD&ProdID=36