If your goal is a permanent verified copy, buying a used CD of Countdown to Extinction for $5 and ripping it yourself via Exact Audio Copy (EAC) is the gold standard. That method is 100% verified because you control the source.
And whenever someone asks, “Where can I download Megadeth albums that actually sound right ?” Alex just smiles and says, “The system has failed… but I know a guy.” megadeth albums download verified