I hear you on that, mines only 6" but it's two layers of limo, so it's black.
In order to avoid noise in your dusk shots you want to shoot at the lowest possible iso you can. If you have enough light to shoot the shot with a fast enough shutter to not have any camera shake (cause that's what humans do), at iso 100 great. I think you probably would have had to bump to at least 200, if not 400 to get a shutter up over 125. In that first one. I didn't look at the exif data.
I have to shoot at 125 or faster hand held because I have a natural shake. I've shot with guys that are like stone, can shoot at 1/25th of a second hand held and get tack sharp images. I'm jealous, but they do all sorts of things to be able to do so. Lean on a wall, prop their arms on something stationary, take deep breaths and then hold just prior to actuating the shutter.
You car color will pop better in extreme contrasting colors. Black, Bright white, Deep burgandy's. Remember because your car is lighter and a midtone grayscal sort of color, in order to define it's lines it needs that contrast. If you put the car in front of a black wall, the edge lines of the car automatically get popped because of reflection.
If you want to understand that more, try shooting a drinking glass in front of a white back drop, then shoot it in front of a black back drop. That's an extreme example, but opens the mind to understanding how light and color reflection can make huge differences.