Lets face it. Cars will always loose "Joe Public" millions of pounds...
High performance & luxuary cars always tend to depreciate quite horribly, especially in the first three critica years of its life.
Once a typical performance japanese car has become three years old its expected that it should (in good condition) be worth around approximately 60-70% of its original selling price. Dealers may add an additional 5% premium on for their profit. From 3yrs on cars then depreciate much slower until they get 10 yrs+ where they plummet to almost worthless in some extreme cases.
If you take the R34 Skyline GT-R V-Spec Uk supplied for £54,000. A three year old example shoud be as low as £32,400 and go up (depending on examples mileage and condition) to £37,800. At a dealership like Middlehurst you could therefore still expect to see cars selling for as much as £40,500. And rare examples that have had very little use could even top £45K. If the cars are less than 3 years old you can add a few thousand on too. From here on in the prices will become more stabe and depreciate per year will be much less, (probably £2,500-£3,500 per year).
And ofcourse lets not forget, people love to tyre kick because for most people £40K is still too much and they will no doubt be dreaming about when the time they can buy their dream example (say in 5 years from now) for £25-£30k.
Just my 2p's worth...
Trev