I don't like the color of the grout on my bathroom floors. The grout line is 1/4" wide. If I were to have it changed to a different color from dark grey to white: (1) would the grey still show through (2) would it mean that some of the tiles may break (I don't have any more of those tiles) (3) how difficult is it (4) how much can I expect to pay (5) would you recommend it? Thanks.

They make a paint for grout but you'll have to go to a tile store to get it. You paint it on the grout lines and that's it. Let it dry and your done. They also make grout stains but you only change the color slightly, as for regrouting, the grout want be think enough to stay together and will just rub off, and the other color will show through