If you are based in Mumbai and are looking to buy a top-of-the-line Hyundai Santro Xing, then probably you should visit Hyundai Motor Plaza at Lower Parel.
The discount is being offered on the car since the car is a few months old and has been on display in the showroom, so the dealer couldn't sell off the car. The car being in showroom is likely to clean and maintained. So it isn't a bad deal to go for.
