One thing to keep in mind when comparing SSK/AIP (SSI) are the ROE's of the exercise. The SSN normally is the one that has to enter the area while the SSI is already there. The typical situation is that the SSN enters the area at a high speed then slows down to patrol. Unfortunately, this gives the SSI the advantage of being able to know when and where the SSN is. Must the SSN always use its coolant pumps? That could be a condition of the ROE's.
Remember, the 688I's below (I think) 8kts can run without using coolant pumps so, it is very silent. The USS Seawolf and Virginia can run at 20kts without needing coolant pumps! Plus they ALL are trying to catch up the USS Ohio Class boomers in lower noise levels. Boomers are a class of sub that no country really talks about but, the importance of their mission means their countries are willing to spend all sorts of money to keep them "state of the art."
Also one thing to keep in mind when judging SSI's, what is the age of the designs?