detailing car what to use after clay bar?

Unless your paint is in excellent shape, you should at least attempt a light polish. You want total clarity, at least whats pleasing to you, before any sealant is applied.....
 
What condition is your paint in? Any swirls or scratches to speak of? If your paint is in great shape with only very minor swirls I would try step 1 and step 2 of the Meguiars Deep Crystal system and then top with NXT. I think you will be more than pleased :nice: