Dubai investor's dilemma: Hyderabad total cost confusion

₹1.8 Cr for a 3BHK in Kokapet from Prestige Group – that's the quoted price. I'm based in Dubai, can't do site inspections. How much more should I factor for stamp duty, registration, and those 'hidden' possession charges? Is a construction-linked payment plan smarter than a larger down payment for an investor like me?