Unfortunately, your screenshot shows off one of DC's bugs - don't worry, you didn't do anything wrong and it won't effect gameplay - it's just that the strength should be '25' and not '25 97'.
To make an item that returns the stat back to it's original state takes a few more lines of script. You would need:
upon activation(ready)-
GET stat
Store stat as ASL
SET stat
upon de-activation (unready)
SET stat to ASL
One thing that Nol Drek did for his SHUA worldhack (Super Hero Unlimited Adventures), was to make all of the 'powers' cursed items so that they couldn't be swapped around between characters. That wouldn't apply so much to items that give powers, but I thought I'd mention it.
