Obviously, any racquet will change with lead, but are there any racquets that you thought were absolutely crap in stock form, but changed a lot with the addition of lead. For me, the Prince Tour Diablo Midplus. Stock it's horrible (except for serving) in my opinion. Way too headlight (10 pts), not enough mass to block back pace. Sweetspot is small, and it's unstable. In fact, I think the sweetspot is smaller than the Diablo mid (my usual racquet). Add about .4 or .5 oz lead to the upper hoop (starting at 12 o'clock and extending equally in each direction) (makes the racquet about 12 to 12.2 oz), and the racquet is terrific - massive spin and controllable power, great volleys, good defensively (reaching slices, simple block backs, half swings), and serves even better than the stock version.