I reckon it's a nice photo of a nice car. If you were going for the random nice car pic in a car-park I think you nailed it. However if I was being picky the reflection of another car in the door looks naff as does the car parked next to your friends car and the poles in the background do not look good . Other than that it's a cool a pic and the sky looks great.
I agree about the car in the back.. Is a bit distracting. Also im not sure, i might just be me, but the vignette seems unnatural to me. If there is more of a feathering and a bit of a increase of the radius, it could do it. Awesome car by the way.
one important thing to think about when yup make HDR photos. minimize the glow around object as much as possible. it makes your photos look unprofessional. ist not very bad in your case, the rest of the photo is good enough to balance the quality ( well accept the reflection and unnecessary distraction like the second car) but you can do it better. plus i think that photo is skewed to the right and that also is ruin the effect.