Don't know about Elantra's parts quality, but can say that Atlas paint quality done on Civic X is really bad and does not age well. The color fades off within 2-3 years and gives an impression as if it is repainted.
Honda Atlas used to be a good company but their quality controls have declined a lot and apparently they have been cutting corners since last few years. Maybe an effect from change in control to the group's 2nd generation that seem to be more concerned about minting money in any way they can.