I've got the KU31's as well. Now done about 6000kms on them.
I'm sure there are better tyres out there, but pretty impressive for the price.
A while ago I thought I would replace the front 2 as my traction when cornering was poor. After putting in the front brace, I've a new respect for how good the tyres can be (again for the price). Think they won't last long on the front, but thats more to do with how I drive than anything...