I'm a big fan of the XK.
Because of mileage I do and ferrying a two year old here and there I went for a BMW 535d.
The torque is pretty amazing, the twin turbos help plus its economical. It should make close to 350bhp and over 500lbs of torque once mapped too, the only bad point is some scumbag broke into it Birmingham last week and now the anti trap on the window is playing up and the airbags lights on