THE trend towards tarting up cars is creating confusion in the trade.

To the point that a growing number of models are becoming difficult to value and tricky to sell.

That's the view of industry analysts Glass's, who cite models like the Vauxhall ADAM and Citroen DS3 as examples of models where the wrong kind of cosmetic choices can have a dramatic effect on values.

Valuations chief Rupert Pontin says: "Factors such as colour have always had a large impact on residual values, but the trend towards increasing visual personalisation is magnifying the effect.

"You could have two Vauxhall ADAMs that are ostensibly the same on paper but, in the metal, are clearly hundreds or thousands of pounds apart in value because of choices that the original buyer made.

"There are some very cosmetically compromised cars around with colour, trim and wheel combinations that looked good to the first owner on the original order form but are not so attractive in the auction hall."

Pontin points out that the appeal of these vehicles is so subjective that it is difficult to know how individual buyers will react.

He says: "The mauve supermini with a tartan roof and yellow wing mirrors running on 13-inch white alloys might look horrendous to a middle aged man like me but great to a 17-year-old who has just passed their test.

"The problem is that the trade finds it very difficult to know how to value some of these vehicles so will tend to price them down in order to minimise the financial risk."

A possible solution would be for more dealers to guide new car buyers towards choices that would be more saleable on the used market.

"Part of the fun of these vehicles is being able to specify all kinds of options but sometimes dealer sales people must know when they hit the order button that they are creating a dud," adds Pontin.

"They arguably have a duty to point out to the customer that some of the decisions they are making are very likely to have a direct impact on the resale value of their vehicle."