budgie smuggler

I have inspected my exhaust found a leak in between my up pipe to turbo and next pipe towards back box.it just seems a bit rusty around joint but still solid would I get away with a new gasket or quick repair not sure if there were nuts on what seems to be bolts through joint.its on a wrx 02 bugeye turbo sportwagon.I don't really want to take pipe off.what's the deal regarding cats and mots do I just need one on which one is better off car is it the up pipe to turbo.