Has anyone removed the roof rails on a 22-26 Lexus NX 450H? I’m looking to remove them to get them painted black. Do you know if the headliner needs to come down ?

Yes, headliner needs to come down. Major undertaking. I vinyl wrapped mine with 3M gloss black. Pretty easy and look great.

Can u provide product link? Did u do it yourself?

DYI. Get 1x5 ft of vinyl black, cut some ~4" strips, flatten from the top down and trim with blade. I covered all the chrome on mine and rails. Rails were by far the easiest to do.

I vinyl wrapped mine w/o removing them.

Is heat gun necessary?on racks did u glued/fixed left and right side at the same time or started installing from one side

No. Clean the rails w/ alcohol. Put blue masking tape on the edges so you don't cut into the roof paint when trimming the vinyl.