Xslimmer is on my MacBook Air and my iMac 24/Alum with ZERO problems. I actually run it a few times a week, as I add this or that, to try things out. And it hasn't been a problem whatsoever with my 500G Time Capsule either.
Some of the savings it gets on installed apps are amazing. I HIGHLY recommend it over all these kludge type manual installs and erases. In a few clicks, my entire drive is scanned, every app that can be slimmed is, and it all takes just a few minutes.