Thanks Fouad. Sorry for the delayed reply, i was caught up with other stuff. Car is a 2009 Honda City, black interior. Carpet is mostly clean. To start with, i want something like a quick detailing spray for the dashboard, door panels and other plastic surfaces inside.
I have been through the thread and all i can say is - excellent work! Regarding photography,
1. You might want to read up on circular polarizers for avoiding reflections when you don't want them.
2. Since your subject, the car, is stationary, you can increase the exposure time instead of increasing the ISO. Though you will want a tripod or some other surface to rest the camera on for this. Table will work too.
3. Try with the lens stopped down a stop or two. I.e. if maximum aperture is F/4, try some pictures at F/5.6 or even F/8. This will increase the sharpness and depth of field.
4. I don't know a thing about photographing cars, consider the above some general tips.
5. Are you taking the JPEGs straight out of the camera or processing the RAW files?