Hi all-I've a plain jane Focus and a ZX2 which I REALLY like!

I really would like to have a listing of the mechanical technical differences between the various engines, My ZX2 has more ponies than the plain jane model OK--WHY? I hear the cams are hotter great! better than the later more powerful Focus? what was done to get the bigger numbers? I'm not after a dragster but if I can gain a few--so much the better!