I have de-badged all of my trucks and love it, I have always used fishing line and goo gone. Never left any scratches. The only thing is if the lettering has been on for a while you might have some ghosting. But that you can just buff it out...
[ame=http://www.youtube.com/watch?v=hoJgPch5NzU&list=UUgEcPol_nG9_aFJbB8ameLg&index=26&feature=plcp]Chemical Guys - Hybrid V7 + Blacklight Radiant Finish Protection System - YouTube[/video]
Here it is I think.