My Gurugram 3BHK hunt: Hidden costs are non-negotiable?

₹1.8 Cr for a 3BHK in Sector 52? Builders like Paras Buildtech quote this, but nobody talks about the *real* negotiation ceiling. I'm told 2-3% is max, but then PLC, parking, and maintenance charges add another 15-20%. Are these "hidden" costs just non-negotiable price hikes? Change my mind.