In my case I went from a TVR Tuscan 2 to the 4/4 so really the difference in performance has been very noticeable.
It's not the car's fault but mine alone.
Having said that, i do find the 1.8 Zetec very lacking when you need that extra bit of power for overtakes etc.
I guess that would be a bit of a difference, probably requiring a very different driving style.

I recall a few years ago going to test drive a cerbera, I drove to the dealers in my rav4, the cerb took my breath away, going home in the rav4 felt rather pedestrian!!