GOT A P0134 CODE FOR 2013 VW CC. IS THE DEALERSHIP QUOTE OF 1400 ACCURATE?

Without having hands on testing, it's impossible to know if it is accurate or not. It is plausible, but automotive diagnosis and repair is a very trust based situation. You need to develop a relationship with a shop and technician that is straight forward and communicative with you, and shares with you what is wrong and in basic terms why, and what the risks are if the job is undertaken -- is there still a chance of further issues? Honestly, I'm not even seeing a P0134 listed in the shop manual for this vehicle, double check the code maybe?