Honestly, the OP's image is better than any of the ones you posted for a number of reasons. (IE: HERE: https://photography-on-the.net …/showthread.php?t=1017337 )
He could refine them by adding light sources and changing his placement.
Example of one of my shots.
LARGE: http://www.flickr.com …in/set-72157616871983139/
2 lights. Did not spend hours removing any flash highlights because there were not any. Only subtle accents on the front bumper. Terrible of you to try and convince someone to NOT use lighting.
To the OP, keep trying and going your direction. Work on setting up multiple sources, and using ambient light as well. Learn to control your light sources with your surroundings. Take it back a notch, use some shoot through umbrellas or softboxes to decrease the harsh highlights.
Removing the backgrounds is one of the most novice things you could do as a photographer. Work with them.
Also work on your composition and leveling. you're on the right track. I also read you are light painting. If that is the issue and you are strapped for cash for more gear, you can also put the camera on the tripod, shoot one side with a stationary strobe, then reposition the light on the other side or where you prefer, take another shot and then stack them in PS.