Hi.
I planned to buy front air dam and side and rear aero flares on that site.
Do they sell prepainted kits?
Or should I paint it after purchase it?

And, does anyone know how much should I pay for installing body kits
at Mazda dealership?

I think I cannot install it by myself.

Thank you :)

If you buy the Mazda parts from your dealer they will come pre-painted.
Also MAZDAPARTS.COM is the same thing.
As for how much it will cost ,,,call a few dealers and see what they will charge you.
You could always find a good bodyshop and inquire with them as to a price.