It's simply the difference a well integrated design can make.

There are many other factors contributing to the performance of a vehicle than the engine and it's respective size, or even horsepower rating alone, and all parts of a vehicle must function together in concert.

Each part must be the perfect size, weight, strength, etc,..  It must even have the right price, and appearance.  Otherwise it will not operate efficiently within the intended scheme.

Don't take me wrong,.. I'm not a Ford fan, but a good example of this is the previous generation of Ford's Mustang.

It may have started out as a kind of bad joke, (as the Mustang II, a variant of the Pinto) but FoMoCo's product engineers carefully refined and re-designed every part of the car, year after year, until the last few models were so well integrated, that now although "5.0" is nothing more than a description of a tiny engine by American automotive standards, the moniker has become famous,.. even a household word!

Stop now, and think about the significance of that for just a moment...

In fact the "package", performs *so* well that some police departments (for their own safety) refuse even to pursue these cars in a high speed chase.
Some others just buy their own-- (or confiscate someone else's).

There are many other examples of course, but hopefully I've been able to help you understand the vital importance of practical
"holistic" engineering.