German tuning house Carlsson has turned its hand to a full-on bespoke model for the first time with this, the C25.
The C25 is still broadly based on an SL65 AMG, but gets unique, fully carbon fibre bodywork - only the windscreen is carried over from the SL. Things are more recognisably SL inside, with the basic dash architecture coming more or less straight from the Mercedes, but most surfaces have been heavily and expensively retrimmed.
A lot of work has gone on under the bonnet too, with the bi-turbo 6.0-litre V12 now pushing out 772bhp and 850lb ft - figures that are 168bhp and 113lb ft up on the SL65.
It's enough to push the (ungoverned) top speed to 220mph, at which point the underbody aerodynamics produce no lift at all.
Each C25 will be extensively tailored to suit the tastes of its owner, and Carlsson is permitting just one example to be sold in each country. A total build run of 25 is planned, with the factory capable of producing around eight cars per year.
If the small production run makes the C25 a pretty rarefied beast, then the price is only going to add to the car's exclusivity - to get your hands on one you're going to have to part with £390k before local taxes.