SPBWatcher is not included but i have attached it below
also take a look at the skin package here
http://www.imarche.net/omnia/index.php for a great theme switcher.
If you just want to uninstall S2U2 then go to add/remove programs and do it from there. You may need to manually delete some files afterwards though.
If you want to delete everything then best route is to do a hard reset and put phone back to factory default. Go to settings / system and you will find the hard-reset option.
Main memory is the phone's sotrage area and is very small
Storage memory is usually the 8/16gb area.
I would advise installing as much as possible (if given the option to) onto the storage area to avoid difficulties later. SPB and S2U2 can be installed onto Storage area.