the reason VW didnt put the supercharger into the production 16v was due to costs. 16v's when first released where already being sold at a loss!!
16v engines are not as complicated as you think. once you have an understanding of them you can easily work your way around them
16v's are just generally better spec'd cars as std, and engine wise a std 16v never has less torque across the range than a std 8v
k-jet was designed around performance & responsiveness
Digi was desgined with efficency in mind
the 8v box is just as weak as the 16v box. its the diff rivets that are the weakspot in all them. the reason the 8v boxes dont go is because they aint put under as much strain as with the 16v.