You're just p***ing money up the wall running them on the road.
Those Dunlops Ian mentioned are superb, I'd forgotten about them - friend of mine runs them on his LCR track car and over the past 5-6 years of ownership they're the best he's found. I think they suit a heavier car.
Again, this is all down to personal preference in terms of feel/grip and how you drive. Start sawing at the wheel and driving like you're in a Bond film, you've got a very expensive day on your hands no matter what you've bought.