My 2BHK hunt: Gurgaon resale negotiation?

Two years ago I'd have laughed at these prices. Now I'm seriously looking for a 2BHK in Sohna, Sector 32-33, maybe a True Habitat project. My budget is around ₹1.2 Cr. I'm wondering if secondary market deals are actually better for negotiation than new builder projects. Dealers are saying you can get a better price on resale. Has anyone had success knocking off a significant amount on a resale flat in Gurgaon? Like, what's a realistic percentage? Also, is it better to go through a broker for resale or try direct?