I´d almost given up on my strat trem, it just couldnt handle more than a gentle vibrato before getting my guitar out of tune.. SO i let a luthier take a look at it and he did a full setup and widened the nut slots...

The whammy bar can now be used to full effect and I have yet not been able to get it out of tune, even after a sweaty JCM800 session with lots of dive bombs!

And the setup was perfect as well, the guitar is smooth as butter now! :