It would be unfair to give a verdict here as the Tata Hexa is not launched yet. So, we would suggest you to wait for the official launch and stay tuned for future updates.
For the availability and prices of the spare parts, we'd suggest you to connect with the nearest authorized service center. Click on the link and select your desired city for [service centers@https://www.cardekho.com/Tata/car-service-center.htm