Getting a gutiar routed and fit with a whammy bar is a major understaking - not just a matter of drilling in on - you have to scoop out a cavity at the front and at the back. If it's slightly out then the guitar will never be set up correctly. Unless you know a luthier who is going to do it for you I would say forget it. As for the difference between whammy bars and whammy pedals goes - it is huge. The effect they produce is totally different. A whammy pedal won't allow you to recreate ANY of the effects you get from a whammy and likewise, you could never make a whammy bar sound like a whammy pedal.