Hi i have had new injectors fitted a good few years back -genuine audi (not cheep) i have probably done 100k miles since. Knowing the amount of work involved i don't think i would fit second hand units. The injectors may be the same but may not--The fuel rail is part of the manifold so unless thats damaged you wont need that but you will need tip seals and the brass seals that fit the rail. You could get your injectors serviced but not that many places can do the high pressure injectors.
What has led you to needing new injectors ? Getting back to the golf and any other FSI badged car--i believe that they are not the same FSI as the A2 but just direct injection without the stratified cycle.
cheers mike