It doesn't really matter what the old one is if you're going to replace it. It's just that you can move a new two piece toilet in pieces to get into tight places or carry up stairs for example.
To get the old one out, I've broken them down into pieces using a hammer and sticking pieces in a 5 gallon bucket to carry them. Just make sure you shut off the water and drain it completely before you do it!

Do you have a second bathroom in your home?