Typical German car nickel and diming for every feature.

Head design is a big one. Look at a fox body Mustang 5.0 and a current 5.0 ; DOHC, variable cam phasing, and direct injection. Put sophisticated intake manifolds on there (which go back to the 80s as a widely available tech) and you get a lot more power, when you consider things like the higher compression ratios the tech enables.