I think people are being a bit simplistic in saying players only go to Sarries or stay at Sarries because they are getting paid well (whether legally or not).
Players who are interviewed, both Sarries players & players form other clubs ALL say that Sarries, irrespective of money, are a great club to play for. Nothing is too much trouble, the H&C is superb (think about how quickly injured Sarries players come back?), the club look after the families & no detail is too small. Journalists all say the players themselves & the coaching team are approachable, polite & all round nice guys.
In short they behave like a proper rugby club in many respects.
I'm not saying they are adhering to the cap, but its clearly not just about the money (although I'm sure that must help a lot!)