I bought a new current model s450L in November as they were trying to shift them so they could bring in the new models so I got £30,000 of the list price.
It has the new 3.0l straight 6 twin turbo engine from the C43 plus a hybrid electric motor charged when you apply the brakes. The electric motor adds 150 lbs/ft of torque at all revs giving 400 bhp and 520 lbs/ft of torque. It means a 0-60 time of 4.8 seconds and 165mph top speed which is not bad for a 5.3m limousine weighing 2.7 tons. 28mpg too and no plugging in.