Hello
Gprs are ok but you have to remember that they are a trye designed in the 1990's and realy there are a lot better these days, I have used gprs on road and track there good but the michelins for instance are miles ahead. Think if your only going to use the bike for fun at the weekends get the stickey rubber, michelin cup or dunlop 208's.
I havent tried them yet but have ordered a set for my super mote are the pirreli diablo's I have only heard nothing but good things about these and if your mad enough they also do a corsa version for the track, These days small tyres are all about the same money, do you want to do 4000 miles? or 2500? I suppose its all down to your supplier and what they acn get hold of, but i would try others before going to the dunlop gp's
just my opinion
luke