Fitted these to my worked BRZ (255/35/R18 rear | 225/40/R18 front.
Very comfortable and minimal noise. Quite a progressive tire in the dry (although not as much as the Toyo R1Rs and Brigstone RE050A's I've had on previous cars. Albeit much cheaper!
However the wet weather performance is surprisingly poor. I have less rear end grip with these 255 tires than I did with the stock 215 Prius tires that came with my BRZ. I think I'll go for a KU39 next time.
Overall I think they are OK for a reserved driver, or someone who wants to have fun in a relatively low powered rear wheel drive vehicle like a BRZ,FRS or MX5, but this is not what I would consider a High Performance tire, as Kumho's marketing would indicate.