I just removed my decals, and used a "Goof off" type on one, and 90% Isopropyl Alcohol on the other. The generic Goof Off didnt work at all.
The alcohol worked like a charm, and where it was the only solvent I used it left no odor whatsoever. The Goof off side now stinks.
So in case anyone is still thinking about this, I'd recommend using Isopropyl alcohol first.
Retired: '00 e46 (5mt)
Current: '07 e92 (6mt)
Next: F10 or F30?