You don't need to swap your bridge, just tighten the springs all the way so that the bridge is right up against the body, then get a chunk of brass (or even wood, which is a helluva lot easier to work with, but probably doesn't give the sustain) and file it to fit in the cavity between the trem block and the back of the routing. If it's filed to fit it won't slip, and the back plate will hold it in. Of course, much as it would improve sustain, I like the ability to do the odd surf style vibrato. If I wanted a hardtail guitar I would've bought one. In fact, I do, and I will. But I want a trem strat too, and I love mine just how it is.