I need to add. check the calipers because the mk3 handbrake cable also splits letting in moisture and it then freezes!
although I agree with mk4 calipers being better than the mk3 one's although they also have issues with seizures!! (goodridge do a hose kit for about £30 if you want to go mk4 although I would go for the full kit which is around £80)
I believe well maintained mk3 calipers work just as well myself (keep the handbrake mech clean and lubed and you shouldn't have issues)