Why are you selling it? I mean I think about selling mine all the time but I know I wont. Just make sure there's no chance someone can tell it was once modified because you'll get a lot more money for it.
How much are you planning on letting it go for? And do you have any specific parts off your car that you're going to sell?
Yeah do a all out detailing job from the engine to the interior. Oil change and trans fluid(only if it has a dull colour) Get rid of any CELs and I think thats it...