It's not clear from your post whether or not you currently own a Cakewalk product
If you do then you'll qualify for an upgrade at a cheaper price than the full version.
The upgrade is a full installation and not an add on to a previous product.
If you do have a current product, leave it on your system - don't delete it (ever!) if you're going to install X2 - there are shared folders which X1 & X2 need in order to function properly.