Are these those super-quiet subs that has got the USN worried to the point of leasing one of them for study and sonar signature recording?
The USN leased a Swedish submarine which uses a different silent propulsion system. The German system is arguably quieter and has reportedly greater endurance.
In a manner of speaking. Type 214 submarines can have the same kind of air-independent propulsion as the Swedish submarines have.
Yes and no. The export models lack some features, like the antimagnetic stealth hull, but they have the AIP drive.