Hi Andrew:
You do not replace the roof; they cut out a section of panel. This method of construction is not that different from other manufacturers except for the ultra clean laser welded seam that is created across the entire roof edge and a smoothing filler that is baked in with the base primer vs. most that still spot weld and cover the mess with a rubber strip for cosmetics and a water seal. In particular, you have to run your fingertips down the length of the seam and the creases to feel what W accomplished. None of this is a simple crease but a very unique multiple contour edge leading into the crease from above and below.
I also liked the new windshield inlay. Most manufacturers are heading to this for cost and simplicity and it just looks cleaner.
Rfruth, ULSD is the only diesel I know how to purchase nowadays. High sulfur is "probably" available at many locations but not at the gas stations I have visited recently.
Tim, the reliability is a top priority for VW because they know there is a history. All I can say is the car did not squeak, rattle or twist and I was hitting it hard (well in NICE-On’s and Fuel cut hard anyway

) coming out of that mountain range!
There are only two mid-size vehicles I would consider right now. That being the 2012 VW Passat TDI w/ a stick or DSG based AT and the Sonata with a stick or Hybrid.
Wayne