Hello wilbous. Was the original that small when you started working on it? If it was you should really try to work on something way bigger. Most people only work on pictures larger than 2000px wide, sometimes up to 8000px. it makes it easier to work on and easier for us to look at. If you work on pics 8000px wide please don't post them that big.
The chop looks good. I like the background and the atmosphere. I have two problems with it, the first is that the car seems a bit squished and the roof seems taller in your chop than on your original. I don't know if this was intentional or if it was an accident. Remember if you're resizing something in photoshop through free transform hold SHIFT so that you don't mess with the proportions of the car.
The second is the shadow under the car. It's way too sharp and should be blurred.
Keep it up.
