I'm sorry mate, but then... why do you post examples with
1) ...a very busy brick wall and seemingly an antenna sticking out of the roof of an otherwise very flat looking car?
2) ...a nice eye-catching "No Entry" sign next to the car that, BTW, is in the shadows whilst the wall in the background is in direct sunlight?
3) ...lots of grafity on one side and some eye-catching posters on the other wall?
4) ...a very dark undercarriage that seems to lack a lot of detail, especially with these very deep shadows on the floor?
The car should be the eye-catcher, not it's environment. No lines leading away from or into the car (mind road striping, floor cracks etc). Car should be clean, spotless. Your images should convey the message: "buy me"! And if it has any special features (I bet a "limo" would have them), take some detailed shots too.
Here is a nice list of do's and don'ts - even though it's talking about a Mustang, the basic
rules are there for every car.