Might sound like a bit of a left field suggestion but Uniroyal Rainsport 5s. I ran RS 4s for 2 years on an Exige V6 and we now have RS 5s on (the replacement). Have seen Uniroyals murder everything in sprints fitted to TVRs and the like so although they are soft and rain focussed, they do work in the dry - certainly well enough for road use. In the wet they are terrific and not expensive. And they come in 17s and 18s as required. As said - a bit left field but speak as you find. Good luck!