Renault Kwid has a metal body build. For a better idea os drive quality, you may have a test drive of the car by visiting the nearest dealer in your city. You can click on the following link to see the details of the nearest dealership and selecting your city accordingly - Dealers.
Exact information regarding the prices and availability of the spare parts would be best shared by the authorized service centre personnel. Follow the link for service centre details and select your city accordingly: Renault service centers