There was a documentary on Discovery Science a few months back about how they made TVR's and how they are generally not available in the US because of the lack or airbags etc.

They had a great method to demonstrate power.

The stick a $20 bill (20 pounds in the UK) to the dash in front of the passenger and if s/he can pick it off under full acceleration they get to keep the money.

Several tried, all failed. I like the sunglasses method too though.

 

Simon, with some of these cars the $20 bill can come of the dashboard and wind up in your lap!!