I am going to sell my low mileage(7400 miles) 2008 MX-5 Miata GT RT. I want to know If I should fix cosmetic items before posting it for sale, I.e. some paint scratches and a small dimple on a door and a scratch on the roof. It would require having the door and roof spray painted or should I simply offer to discount the price for these items.

I would never spray paint them. its better to have a scratch or two than a square of spray paint. without seeing it I cant tell but is it possible to just use a bit of touch up paint? if they are small you might want to ask a paint shop about that. Depending on your asking price it might be worth it to get it touched up since its still rather new so it will sell well if it looks perfect. If not, set a price and try to sell it, then if no one buys it, look into how much it would cost to get it repainted/redone and if the difference in price is worth the money thats going to be made....