As to the missile boats, they are fast and stealthy and those four missiles they carry are very dangerous. They are building them in large numbers now. My guess is they will be used in the close in work against places like Taiwan and islands of the S. China Sea to keep our, or our allies, larger surface combatants at bay.
Unless caught completely unprepared and flat footed, they would be hard for a sub to take out. It would have to be airpower and they will operate close in to shore under heavy PLAAF cover.
RE: "As to the missile boats, they are fast and stealthy and those four missiles they carry are very dangerous. They are building them in large numbers now."
So, I am riding on a ferry in a corner of the Pearl Delta and lo and behold, what do I see literally sitting on a mud flat, being completed. A hull. For those who have not witnessed the typically Chinese ways of using many small low tech tasks to build something high tech, it will come as a shock when the harsh reality becomes undeniable. We in the West have nothing to compare this to in our easily accessible experience. The last point in history where the East was this strong and ascendent was back when we were in the Middle Ages.