Retrofitting roof rack with rail

[mrche]

Hey Guys, looking to retrofit a "roof rack system designed specifically for use with roofs that feature rails" to my 2015 Mazda 3 sedan.

any suggestion how can i go about doing this?

can i get a rail for the M3?

or easier to just buy a M3 cross bar and sell this?

[studum]

or easier to just buy a M3 cross bar and sell this?

Yes