Re: 6 Cylinder Producing 350HP XKR a supercar,lol. The only real supercar they have is the xj220. It's a six cillinder with more then 350hp yes, but it has 2 turbo's so that's not that very good. Look at the mclarenf1, it has a BMW engine with 627hp without a single turbo or supercharger out a 6,0. Jaguar can't make such an engine not without turbo's... Jags are no real drivers cars.