Hello, I just purchased a home and it has the vinyl flooring and I would like to rip that up and put in granite tile. I noticed under the vinyl is wood, however it appears that if I were to put the tile over top of the wood then it would be higher than the joining rooms. Should I rip up the wood? I'm not sure whats below it..

I used to consider myself a pretty good amateur tiler, but with the last couple jobs I've done I've been less than satisfied with the way the grouting part has come along. I can't seem to get the grout to uniformly fill the space between two tiles anymore. After 20 mintues or so when I should be wiping off the haze I find myself re-applying left-over grout that I had all but thrown away to fill low spots and spots with air holes. It is so frustrating. I'm not doing anything different tham I used to so...going over the tiles on a diagonal to the grout lines with the rubber float at 45 degrees to the floor. I pass over the tiles in every which direction, back and forth, left to right, this way and that way, and so I must be packing it in pretty good, but I can't seem to get the grout to be level with the top of the tiles. Any ideas? Thanks.