I just removed my factory TRD stickers from my truck bed. I tried the hot soapy water and scrubber W/ rounds of Goo Gone in between scrubbing. I got most of it off but I still had to use some polish and elbow grease to get the remainder off. My truck is a 2010 so it has definitely had time to adhere to the vehicle pretty well. In the end, the polish removed any stubborn spots and helped even out the clear coat in that area.
I use the same process;
I use a heat gun. Just be careful of getting to close, you can damage the badge/paint. Fishing line works great, but with the heat gun, never really needed it.
WD40 works amazing on the goo left behind. Theres no chemicals to damage the finish and cleans easily with soap and water. Just saturate a spot on a rag, and spray the site, then rub and repeat.