Real estate pro buying own home: Gurugram surprises

Spent the whole Sunday checking out options in Sector 44, including a project by MRG World. Honestly, it's wild how different buying for myself feels, even with my background in real estate. The listed price for a 3BHK was around ₹1.8 Cr, but I know that's just the starting point. I'm trying to figure out the true all-in cost. Builders always quote without stamp duty, registration, PLC, parking. What's a realistic percentage to add for these in Gurugram? I heard some people get hit with 'IFMS' or other charges right at possession, which I'm trying to avoid. Does anyone have experience with MRG specifically, or other Gurugram builders, on these 'surprise' costs? And negotiation, does it even work anymore? Even after pushing, it felt like they wouldn't budge much. For a ₹1.8 Cr property, how much is actually possible to knock off the base price here? Or is it all just about getting a better payment plan now?