it should tell you on the wall of the tyre. look for the dot date, if the tyre is new the dot is red. you will find a four number digit IE (5209) meaning the tyre was manufacted 52th week of 2009, sometimes in small print below or next to that marking will be the max PSI load.
Generally 30 is a good number on the evo's, don't forget there is a 60-40 power ratio so realistically you need to compensate for that added kick n the bends.
As for you Mark, your fronts need to be on 18 so they don't catch your arches lol!!!!
will be going to imperial tyres monday to get wheels aligned aswell, get some camber/castor on them as my old tyres had uneven wear in the inside off the tyres.