its all streight change.
Its always age. I had to change mine too.
Audi you will found out is an exelent car in the point of repair. all parts in the right points and are good placed.
just you need a spring compresor becouse there is a key on top and there is no safe way to take it out.
simply look at catalog.
www.auto2.ru there is one like etka free.
and say to your friend if he didn't do his heater core he should anticipate failure in very near future.