The only part I can answer is the 2nd part, about removing 3.2....
Once installed, you'll have 2 kde directories... 3.2 and 3.3.... There are a few things I had to copy over such as some wallpapers and a few other things, but nothing major. Once I copied what I needed, I deleted the 3.2 directory.
Mind you this is a Gentoo system. It might be a little bit different.