My 3BHK upgrade dilemma: RERA checks for Metro Realty?

Since last Diwali, I've been seriously looking for a 3BHK upgrade in Pune, maybe around Baner or NIBM Road. My current 2BHK in Hinjewadi feels a bit small now. Visited Metro Realty's Kosmic Kourtyard Phase 1. Project sahi lag raha hai, but RERA compliance pe thoda doubt hai. How do you actually verify RERA registration details online? Kya red flags hain jo log miss karte hain? Also, if there are issues, RERA complaints kitne effective hain? Matlab, builder delays ya quality issues pe action hota hai kya? Any experiences with Metro Realty?