i get the impression the zetec is a blinder of a setup and very tuneable. however the yb is a masterpiece and purely for bragging rights, its worth 50hp alone. when someone asksd wqhat engine your running, and you can just say cossie in one word, its enough said. also bear in mind the std internals are more than upto 400hp. after the initial outlay its probably the cost effectrive option aswell. also has the best looking cam cover out of all the performance fords.