Hi Ecca, I just put a Strat together from parts bought at a local dealer and upgraded the trem to a Wilkinson at the cost of an extra £20. It does have the grub screw and I didn't see it at first and rang up to complain because the trem bar was loose, I thought it was crap until he explained what I had to do. I did wonder about the consequences of tightning that screw and you have answered the question.
Regarding the Stetsbar, they do the job great on my Gibson Les Paul & SG, but they are not the same as a Strat trem, however I do prefer them to the Bigsby on my Gretsch. I remember reading a lot of stuff about Jim Burns trying to get around the patents when designing the trem for the Marvin, but sadly I don't think he got it right either. The trem on the Burns is nowhere near as effective as the Fender Strat design.
