hi there
proceed with caution there m8.I had a 1990 16valver with a blow out there .its most likely to be on the down pipes on the flexible area which can,t be welded obviously and has to be replaced and unless u really know what ure at is best left to a mechanic as engine mountains and things have to be removed to replace the downpipe.Also a new downpipe which can only be got through a VW agent cost me ?180 or so at the time.mine went because the engine mountains were knackered,allowing the engine to rock back and forward to much putting excess stress on flexible downpipe causing it to break.So might be a good idea to check the engine mountains out also.to do this put the car in 2nd gear with handbrake off and engine NOT running,rock the car back and forward whilst looking underbonnet at engine,the engine should move about a little bit,say twist about an inch at the top or move up and down about 1/2 an inch,but if its really slopping about then ure engine mountains r knackered.the engine mountains can be costly too unfortunately,ie i think ?50 or so for the front one which is like a little fat shock mounting the rest in around ?25 or so.i can,t be too sure of the prices to be honest as it,s been a while since i had the mk2.let me know how u get on with it m8