Heat guns are pretty inexpensive. They can be bought for $20-30 pretty easily.
http://www.homedepot.com/p/Wagner-HT1000-1200-Watt-Heat-Gun-0503008/100048744
I heated up the molding, emblems and badges then started to pry them off with a plastic tool that looks like a large butter knife and I also used another plastic took that you would use to smoothing out a new sticker, so it looks mostly like a plastic credit card. The more you take your time heating up the moldings and pulling them off slowly the more of the two sided tape comes off with it. I was pretty impatient and mostly ripped the moldings off once they were started. Maybe if I used more heat it would of left less behind.
So once the moldings and emblems were off I used straight gas on a rag and rubbed it on the left over two sided tape and scrapped it with the plastic credit card. Then repeat and repeat. It took a long time on the doors. I think the first one took me like two hours plus. Then the other doors I got done in like 30 minutes each.
Let me know if you have any more questions.
Nick