dont forget metal head gagit too. 1.3mm is the go for the 25. around 400 somalians for this!
just remember too..... you'll need supporting mods like injectors, ecu up grade, metal head gaskit,fuel pump.
dont be tight if your going for a up grade like your talking coz if you do it will only cost you your motor!
my 3 1/2 cents worth!