You can tear the whole thing out - I recently did that. I used a reciprocating saw to cut it into smaller pieces, then carried it out of the house. It actually came out fairly easily. Depending on what you want to replace it with will depend on what you have to do. You could fit an acrylic, cast iron, or othertype of tub, either "normal" or whirlpool, air, or combo. Then, assuming you want it to also function as a shower, tile the walls surrounding it. Depends on how much you want to spend, and how handy you are whether you can/want to do it yourself. Many people do. Underneath the one-piece fiberglass tub surround, there probably isn't anything on the walls. If you go with tile, you'd have to put on cement board. Suggest you take a look over at www.johnbridge.com if you decide on tile.