Diamaris have not been the performance benchmark for some time now. You can do a search, but a lot of folks have been disappointed with them, they wear out faster than Tiger Woods' condoms. I do like Michelin's Latitude Tour HPs. Got a solid 50,000 miles out of my first staggered set, and just started on my second staggered 19" set. They are pricey on the initial outlay, but excellent bang for buck when you factor in the endurance and excellent wet and dry traction. You should check if they make those in a 20".