We would get price lists for the various luxury and high-performance cars and trawl through them. Reckoning on much of this information being available through online configurators, we could fill in the gaps by contacting press offices.

Little did we know that in most cases, pinning down what you'll pay for extras on your Bugatti or Rolls-Royce would be pretty much impossible, with such information a closely guarded secret. Even the press kits for our test cars often omit this information. But undeterred we pressed on to find out what we could, even though some marques that should be here are absent.

However, we have managed to find plenty of eye-wateringly costly options including paint jobs, brake kits, carbon fibre body kits and much more. So if you want to know who charges £7500 for a yellow paint job or nearly £9000 for a sports exhaust, read on: