Gurugram Investing: What's the real deal on negotiation?

I'm based in Dubai and can't do site visits easily, so I'm relying on community insights for my Gurugram investment. I'm looking at Satguru Developers in Sector 105, targeting a 3BHK around ₹2 Cr. My main question is, Gurugram mein negotiation kitna possible hai? Builders bolte hain fixed price, but kya thoda discount mil sakta hai, especially for early payments? Also, possession ke time kya hidden charges aate hain? PLC, OC ke alawa aur kya expect karun? Lastly, construction-linked plan vs down payment, which one is smarter for an investor like me jo rental income dekhta hai? What's your experience?