The best tires you can buy for handling are Bridgestone Potenza S-03's, hands down. On my old RSX, they increased handling to an amazingly high level and also improved accel, decel, road feel, steering feel, ride comfort, and noise levels greatly. I was extremely happy with the tires during the spring/summer/fall months, and the recipient (my brother) of my RSX was very impressed with them. They are the highest rated tire on www.tirerack.com and can be had for about $580 for all four.