Sometimes you have good days. Then other times you're invited to a racetrack in Portugal and given the keys to five classic M5s-actually four M5s and an E12 M535i, but whatever.

When you have a day of such you might be given to boasting or you might find yourself typing down detailed reviews of each generation.

That's exactly what happened to AutoGuide's Benjamin Hunting, who took the opportunity to write about the E12 M535i, and the E34, E39, and E60 M5s.

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