I was thinking about shaving down the lips on a couple of my medium driving crankbaits.  I was hoping to make them shallow divers.  Would this possibly ruin the action of the lure? I know I could just go buy shallow diving cranks but I have a few of the same lures that I'll never use.

probably ruin the action. i have tried this and not good results

Most likely kill the action.   You will put the line tie too close to the end of the lip.   

ahhhh makes sense thanks