you have a clubman kart which is designed to run mg reds only the mg yellow are for roatex or lepoard class which happens to be the quickest classes of all and the dunlops are for senior national light or juniors if your running in the wet best you get the dunlop wet tyres which have nobbys tyre pressure is funny thing depends on the track and the weather average day l would put 14 lb all round cold day 15 to 16 in about 8 to 10 laps tyres will gain about 2lb you can make them come on quick but they soon go off quick as kart will start to slide thats if you put to much air in them have fun