I upgraded from a 2010 JSW TDI to a 2014 Touareg Sport TDI. I loved the jetta, but given my height & arthritic spine, it was harder getting in & out. I love the Touareg. Very comfortable, great drive, more zip than the jetta. Fuel economy drops from 28-30 city to 22 or so & on the road from 40 to 30. There's the whole ad blue thing, but they take care of that at the oil changes so you don't need to think about it. Repairs are supposed to be more expensive, but I haven't had any. I'm planning to do the extended warrantee.
Adding Ad Blue is slightly more inconvenient that adding windshield washer fluid. Do a search to get the video to take the mystery or doubt out of the picture. While consumption does VARY, for me it has been app 4.5 gal per 15,000 miles.
PARTS are indeed more expensive.
So for example, I bought tires @ 89,000 miles for 09 VW Jetta TDI oem sized (Continentals) $535.
Cost per mile driven (retail) of the oem set .00784. consumption of 13,692 miles per 1/32nd in. (10- 3.5= 6.5) i do not know the consumption rate of the replacement tires.
Tires for 18 in 12 VW Touareg (took a nail in a non repairable area, needed to change all 4 tires) were $940.
Labor in this case was the same. Preliminary consumption is @ 18,000 miles per 1/32nd in. (12- 1=11/32nd remaining) So PROJECTION ONLY (take down @ 3.5/32nd in, 153,000 mies = .00614 cost per mile driven tires. So IF you feel for you either or both is/are an outlier/s, substitute with your own figures. I do understand that most wear tires FAR faster.