Have fun!!! Don't forget the Beer.

 

It's really not that bad, just time consuming. The worst part is right before you start putting everything back together; you look at it and you get this sinking feeling and think, "is that ever going to look like a dashboard again?" lol

 

I can't say for sure that you need to do a heater core. I have my reasons: I was a dealership technician for 5 years with VW/Audi... Most cars, when you change the coolant in them tend to have a coolant-y odor for a while... a new coolant odor? Sometimes it takes a while to go away. There may be a small seep coming from a plastic tank on the core that is just weeping some coolant, you may have a small coolant leak in the engine bay that you are smelling... When a heater core fails, it can leak puddles onto your feet of scalding coolant, so it's not pretty when it's a big fail. Still, you saw the pics, it's not a fun job, so I would wait until you have absolute certainty.

Recommended that you pressure test the system with the correct VW tester... pressurize the system to 15lbs. Then, watch for leaks... if it's the heater core, it may drain out of a hole in the firewall, on your feet or just saturate the carpets. But then you would know for certain.