Is the Mercedes-Benz SL600 / 600SL a good investment?

The thesis

The V12-powered SL600 is the R129's flagship variant, featuring the magnificent M120 6.0-litre naturally aspirated V12 producing 389 bhp. The R129 market has quietly appreciated nearly 50% over five years, yet the V12 remains affordable relative to its AMG siblings and far below its original £120k+ list price. Recent UK sales from £21,500 to £40,000 for top examples confirm the entry point is accessible. The model bridges modern usability with classic GT appeal; 'too-new' perception is fading as enthusiasts recognize its iconic Bruno Sacco design and over-engineered build. Best buying opportunities have passed, but the V12's flagship status and relative rarity (versus SL500) give it further room to run within this budget.