can i sand down my spoiler and paint it ?

Sure you can, but it will probably look awful when finished. Stop by a body shop for a free estimate and let a professional handle it.

You can sand and paint but I recommend you go to an auto paint store to get the correct primer and color match paint and clear coat, ask for the correct sanding products if you are unsure and take your time. Don't forget to mask off the car before you paint.