i was thinking that the F1 demonstration works because of the crazy large rev range and fast throttle response. the large range is needed in order to access all of the song's notes.
in order to do this, one could overwrite target engine idle speed RAM values in the ecu via a custom program or an obd cable. i don't think that this route is trivial on the evora, though.
an alternative would be to use a digital to analog converter microchip with the arduino in place of the pedal position sensor. i expect the sensor to be a simple 0-5V output, so a DtoA chip could work directly off of the Arduino power supply.
if you're really lucky, throttle position might be sent from the pedal to the ecu over CAN or LIN (instead of as an analog sensor input)- overwriting command this would be as simple as injecting rogue packets. i guess i don't really know how the evora pedal sensor works in this regard.