It is plug and play and quite easy on LHD car where the fuse box is not in the way.....
On an RHD model you need to pull off left hand side door sill trim, undo a nut on rear seats trim (for which the seat cushion needs to come out). B-pillar trim can stay in but needs to be unclipped. And then the pain begins, passenger airbag switch and surrounding trim need to be unclipped, so does the trim below (as it clips into door sill trim and side trim with airbag off switch in it. Then glove box needs to come out, so first remove radio (borrow your gf/wife's nail files) then for actual whole glovebox (and not just the lid) you need to unclip the centre tunnel trim (just the left side thou), but hey that'd be boring so VW hid one of the screws behind the trim for the air conditioning (which luckily is easy to take off). Then once you have the whole glove box out (screwed on with 6 or 7 screws.... one behind the radio in the glovebox) you can route the cable and remove two wires from the radio harness (they need to be unpinned carefully) and push two from p&p loom in..... and remove iso plug for speaker and plug into p&p harness and the one from harness into radio......
It took me around 2-2.5h without specialist documentation / tools..... looking at the amount dealer has quoted you I'd guess they would be able to do it in 1-1.5h, or at least assume so...... it is doable though but a bit unnerving to take apart your brand new car
