For a Lamborghini sweetener sound effect, take a half liter empty beer can. Squish the can together at about 3/4, closest to the drinking opening side. Hum, sing, mimic a car into the drinking opening. Experiment with the depth of the squish to get the best metallic resonation.
Spice up the rev’s with some lion roars blended in at a subtle level.
See and hear an example here.
– Giel van Geloven