The Smarter Saloon Costs £40K Less New

The E63 S makes the stronger value case before you've turned a wheel. At £167 per horsepower versus the CS's £225, Mercedes was already selling you more punch per pound at list price. The gap between 626bhp and 603bhp is irrelevant in the real world; the gap between £140,780 and £100,500 is very much not. Both cars are now circulating on the used market with insufficient auction data to call a depreciation floor with any confidence, so neither has a proven stability advantage there. What we can say is that the car that started cheaper absorbs future uncertainty better. The CS is genuinely extraordinary — lighter than the standard M5, sharper through corners, and carrying that rarest quality in a luxury saloon: the feeling that BMW actually cared about the chassis, not just the spec sheet. But it is an intense machine, and that intensity has a cost beyond the sticker. It was bought by people who wanted the best and paid accordingly, which means used examples still carry premium expectations on price. The E63 S is the more complete daily proposition. It is heavier, yes, but 305bhp per tonne in a car that can also carry four adults in genuine comfort, handle a British winter on all-wheel drive, and pass for a standard E-Class in a car park is a remarkable trick. It is devastatingly fast, broadly usable, and meaningfully cheaper. Unless you specifically need the CS's track-focused edge, the E63 S is the buy.