Pretty car photos!
#1: Nice. Just level it. Maybe crop a tad closer.
#2: Needs more light on the right - pop in the front wheel? Overall seems a little bit underexposed. What's that bluish patch on the right ground? Is it a processed shadow? It almost looks like the car is sitting on a sheet of clear bluish plastic - like those plastic pads that go under office chairs. It doesn't look natural and distracts my attention.
#3: Best photo. Looks way more natural. Just add some light to the rear and make that exhaust pop a bit. Clone out debris on ground behind the rear wheel. The cloud is kind of weird, but oh well..
I'm not a Vette girl, but you're making me want one.