Ghaziabad under-construction: Builders hide half the cost.

Since last Diwali, I've been seriously looking for a 2BHK in Ghaziabad, especially around Gyan Khand. LandCraft Developers ke ek under-construction project mein interest aa raha hai. Builder bol raha hai possession next year, but delivery risk kaafi lag raha hai. My biggest worry is the total cost beyond the flat price. Stamp duty, registration, interiors – sab add karke budget pura hil jaata hai. Builder ne toh bas basic price quote kiya hai. Honestly, is under-construction property mein hidden costs kitne ho sakte hain? Aur LandCraft ka delivery record kaisa hai? Any past experiences with them and their timelines? Kya ismein negotiation work karta hai ya sab fixed hota hai?