Bengaluru Investors: How real are pre-launch discounts?

Visited DNR Corporation’s new project near Panathur/ORR fringes last weekend. Currently in a 2BHK, thinking of upgrading to a 3BHK, already have a home loan. They're pushing pre-launch offers big time, saying prices will jump after RERA. But yaar, is that pre-launch discount real or just marketing? Also, kitna spot discount expect kar sakte hain if we push? Beyond the basic price, what are the actual surprises for total all-in cost? Like registration, stamp duty ke alawa, any other big costs that pop up late? Interested in other investor experiences. Kya yeh early-bird deals worth it hain?