on those rolling shots use a slower shutter speed so that you get the blurred wheels and the blurred background
dont use selective color...ever lol...Ive have never seen a selective color photo that works. I think a lot of people on the forum will agree with that.
Spend a little more time to find a spot that makes for interesting photos or less distracting backgrounds. Those houses, the powerlines...etc are not interesting. If you have to...use a larger aperture like f/4 or f/5.6 so that you can blur the background.
Something that I recently found out...or experimented with... Using telephoto focal lengths (105mm on my full frame camera) give more pleasing images, better perspective, and a better background blur.
This was one of those images...taken with a lens I paid 50 bucks for....
Now...I posted this because It looks finished but it's not...using the clone tool and getting that little grey power wire near the front of the car out of the picture would be the last step for me.
Im no pro, but I've gotten better from this forum and I am just passing on what I think you can use to help.