Gurgaon builders: How much negotiation is actually possible?

Sohna Road (Sector 70-90) prices are just insane. Everyone glorifies 'negotiating hard' with builders like SS Group, but honestly, how much can you *really* knock off? Is it even possible to get more than 1-2% on the base price for a 2BHK around ₹1.5 Cr? Or is the real negotiation always on things like PLC, parking, or those "all-in" extras? My parents keep saying builders always have hidden margins, but I'm not seeing it. What's the true all-in cost strategy here? Change my mind if you've actually bagged a significant discount!