If I buy a Porsche and drive it in the city rush hour, I accept that I have no right of recourse against Porsche if my average speed is 50kph.

But do I not have a right of recourse if the Porsche only does 50kph on the open road, notwithstanding any express or implied contract terms in the small print about headwinds, winding roads, optimised tyre pressures and the many other things which in practice effect vehicle performance? I would suggest that I would do as its a sports car and I can reasonably expect it to perform as such.

"Unleashed", "unlimited" etc etc are all terms which raise performance expectations in the public mind - which performance is not being delivered.