New Delhi property negotiation: What's the real story?

Does price negotiation actually work in New Delhi? I'm evaluating a property in Paharganj from Mehta Properties. My experience suggests builders often have a margin. What's the realistic negotiation percentage on a 2BHK there, listed around ₹1.5 Cr? Aur stamp duty, PLC jaise charges pe bhi kuch discount milta hai kya? Total cost of acquisition pe focus karna hai.