I'm trying to find better ways to edit gifs. Did you make this one frame by frame, png over jpg and assemble into a gif or did you add the limo as a layer into a transparent gif? Someone recommended gimp a while back, is that what you used here?
Then from the video, imported it into imgflip to make a gif... the shorter the smoother (higher frames per second.) I have another "green screen" effect in a gif that I will be submitting today: imgflip.com/gif/1lanux
Here's my first attempt, I made this using a pie chart/demotivational from imgflip, turned that into a png mask and overlayed on a gif at ezgif.com. All on my phone (at work...) in about a half hour. Will check out Lightworks at home tonight. imgflip.com/gif/1lca67
I don't know what it is, but it look pretty weird! But yeah, both GIMP and Lightworks have learning curves, I think both are useful tools to know after the initial pain. I am no master at either of them, but its cool what you can do with some basic knowledge.