I use z1 as track rain tires. they do not melt like PS2 Michelins used to melt when track dries out, but my set is 2 years old now, I think there is a new version of both rs3 hankooks and z1 star specs now on the market, I did not see many reviews yet from AX people about it.

Z1 generally have better grip in cold conditions and better grip in wet compared to RS3 that are almost r-comp tires in the street mold. some AX people like them for that as they have more grip when warm/hot and absorb heat better than z1 but for my purposes as my car is modified and cannot run in stock class AX anyway I use proper r-comps in hot/dry and Z1 in wet/cold summer conditions. They also work fine at 30-something temperature range but they are not winter tires. Still ,they do not turn into glass at 34 degrees or so like PS2 tires used to do. I think 2014 season may have several new interesting brands but I kinda used to what I have and do not look for new set yet.