If you simply want to watch the main feature film for the first time, you should support the official release—rent it on Amazon Prime or Sun NXT. The quality is reliable, it’s legal, and it signals to studios that there is demand for classic Tamil films.
However, despite its cult status and National Film Award for Best Feature Film in Tamil, accessing Vaaranam Aayiram in its original, uncut, high-quality format has become surprisingly difficult. Streaming rights fluctuate. YouTube uploads get taken down. Blu-ray copies are out of print. vaaranam aayiram internet archive