Check the RERA registrations
Mercury lists three registrations: TN/29/Building/055/2024, TN/29/Building/043/2024 and TN/29/Building/0069/2024. Search them on the Tamil Nadu RERA website and confirm which one covers the tower and home you are shown, along with the registered completion date.
Ask about waterlogging near the site
Perambur was among the localities with significant inundation in the October 2024 northeast monsoon reports, when the Perambur High Road subway was among those closed, and it was named among the areas affected in the December 2023 cyclone. Residents and studies also blame encroachments on canals and the blocking of a drainage channel during the station redevelopment. These are residents' and study claims rather than official findings. Ask about the site's ground level and stormwater arrangements, and speak to people who live nearby.
Check how the metro works affect access
Tunnelling runs under Perambur Barracks Road at depths of up to about 30 m. Ask how it relates to the routes you would use every day, and confirm the metro timeline with Chennai Metro Rail Limited.
Compare the two home types properly
For the 5 BHK floor villas, ask about the land share and how maintenance is charged, and compare them with the 4 BHK apartments on the same campus.
Read the cost sheet
Ask for a written cost sheet with the base price, GST, stamp duty, registration, maintenance deposit and parking, and tie each payment to a construction stage.
This is general information, not legal or financial advice.