A mid-cycle facelift was introduced in 2016 for the 2017 model year. Launched early 2016 in California, the revised SL400 featured a 3-litre 362 hp (367 PS) biturbo V6 mated, for the first time in the SL, to Mercedes' own 9G-Tronic PLUS 9-speed automatic transmission.
An SL500, with a 4.7-litre biturbo V8 producing 449 hp (455 PS), was likewise paired with the 9G-tronic PLUS transmission. The Mercedes-AMG SL63 577 BHP and SL65 621 BHP variants continued with virtually unchanged power trains, paired with AMG's SPEEDSHIFT MCT 7-speed sports transmission with claimed improved shift times.
The SL63 and SL65 were distinguishable from the non-AMG variants by embellishments to their bumper assemblies and side sills in gloss black or polished aluminium, respectively. The SL63 and SL65 also featured trademark AMG 'twin lamella' front grilles and dual twin tailpipe exhaust trims as well as a carbon fibre composite trunk lid.
A slight revision to the folding 'Vario-roof' hardtop operation meant it would continue to deploy at speeds up to 25 mph once initiated and the luggage compartment partition, required to prevent the hardtop components, when folded, and any luggage compartment contents coming into contact with each other, no longer had to be deployed in a separate manual operation.
