Sound from engine while changin g gear from first day of purchase

Purchased Tata XM this October from Bhopal, when I was on my way to home from showroom I noticed strange sounds and poor pickup and different driving modes were also not working in my vehicle so I immediately returned to the showroom where the sales person approached very casually. Then the vehicle was taken to their service centre where they said their is water in the fuel tank!!!!! I was not able to understand that how come their will be water in fuel tank of brand new vehicle. Some how the problem was resolved. but after that their is a noise coming from the engine while shifting gear specially above 2nd gear. And that sound is really annoying while driving. When I approached the service centre they said that this is the common problem in hexa vehicle. If it is so then please make this thing very clear while buying this vehicle that this car will make sounds from engine while shifting gear. Switching gear is also not smooth as in other cars. Overall this car is not value for your money.