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

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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.


"Buying a used car isn't like choosing a new one – there are a host of sacrifices you have to make," explained Tim Bearder, CAP Black Book editor. "That being said, there are certain brands and models (like Subaru) where certain enhancements can add value and attraction."

Jeff Paterson, Glass's Guide editor, added: "It's fair to say that used car buyers aren't interested in buying something that looks like 'Jack-the-lad' has spent that past year revving up and down the road in it."

So which are the must-avoid mods according to our experts? Here's their top 10 no nos.

Bodykits and spoilers

They may have excited the McDonalds car park massive, but grafted on plastic, however well fitted, is likely to seriously damage your wealth.

Aftermarket alloys

While standard alloy wheels add value to your car, picking up a set from Halfords won't. They rarely look as good as the originals and put used buyers off.

Paint job



Like a tattoo, pearlescent paint might sound like a good idea at the time, but see sense and avoid it. It's worth bearing in mind a decent quality, standard paint job as part of a restoration can add value though.

Banging stereo



Although it's tempting to upgrade your "choons", an aftermarket stereo headunit, no matter what the quality, is frowned upon by buyers.

Lowered suspension

Those airy wheel arches might not look great, but slamming your car to the ground should be avoided. Most buyers prefer comfort over looks.

Engine modifications

Insurance companies generally take a dim view to engine mods and are likely to increase premiums because of them. However, there are some buyers that'll be impressed on certain performance cars.

Fat exhaust



A droning, dustbin-sized tailpipe is a sure fire way to lop pounds off your car's value. However, official, manufacturer-backed performance upgrades can be sought after.

Neon running lights

They're becoming more common on new cars, but retro-fitting driving lights turns buyers off as they never look as good as standard fit equipment.

Privacy glass



Tinted rear windows are popular with parents, but blacking out glass all around is seen as a turn off. It's likely to attract the attention of the police too.

Savaged interior



In the hunt for ever-increasing Britney Spears volumes there's a temptation to fit bigger speakers, but the holes they can leave ruins interiors and residual values.

Which of our experts' top five would put you off buying a used car the most? Vote in our poll and let us know.