Which modifications will send the value of your car into freefall?

The temptation to modify your motor can be great, but be warned – the wrong tweaks can ruin your car's resale value.

Personalising your car – be it to make it faster, more comfortable or better looking – is something many owners feel compelled to do. However it's important to remember those modifications are often specific to your needs and can shed hundreds, even thousands, off what its worth.