Depending on your budget there are many choices you can go for. Since you mentioned KU31....I've tried stock, PZero Rosso, KU31 and KU39 on this car, and the KU39 is my favorite so far. It's quiet, comfy, handles well and yet not too grippy. I'm still able to slide the tail out nicely at roundabouts even in the dry (at night when nobody's around
). Bloody cheap too.