The modifications that devalue cars the most

We’re pretty open-minded here at Carwow, but when it comes to mods, there are some we love, and some we’re not huge fans of. Mainly because some can be illegal and might invalidate your insurance, but also because some are just plain ugly.

But, drive down any A road in the country and you could be treated to an impressive display of modified cars – from lowered suspensions to underbody neon lights, and everything in between. So in 2020, we asked drivers nationwide to tell us which modifications were their most hated and which could actually render a car unsellable.

Back then, wonky wheels and headlight eyelashes drew our resentment the most, but we know that things change with time. So, once again, we’ve asked which mods are still grinding our gears, and if another one has been championed our most hated. We also took a look at our internal sales figures to see how modding a car can impact its price when the time comes to sell it.

First up: The mods we love to hate

The nation has voted, and modified exhausts are now officially our most hated car modification. Almost half (49%) of the drivers said that they detest this mod, meaning it takes the unwanted crown from 2020’s most hated mod – headlight eyelashes.[1]

Modified exhausts might be a good way to add some extra oomph to your engine’s sound, but they can make a bit of a racket – a bit too much for a lot of drivers’ liking. That’s probably why they’ve been voted the country’s most hated mod.

Lots of the smaller, decorative additions still dominate the top 10, though. Playful mods like Christmas antlers (hated by 30%) and novelty decals (26%) are still among the most hated. Fluffy dice and novelty horns are also detested by around a third, landing them into the top five.

Headlight eyelashes are still highly unpopular, ranking second overall. In fact, they’re even more hated now than they were back in 2020 – 41% now say they can’t stand them, compared to 32% a few years ago.

The full top 10 most hated mods can be found below:

Headlight eyelashes aren’t the only modification to become more loathed in the past four years. Looking at this year’s results, we noticed that almost every modification on the list is hated by a higher percentage of drivers than before.

This includes the likes of underbody lights, lowered suspension, wonky wheels and car flags, to name a few. Even beaded seat covers are less popular now – hated by 27% of drivers. Plus, almost three-quarters (74%) said there’s at least one modification they can’t stand – looks like mods are more out of favour these days!

Who are the country’s biggest mod haters?

There’s no getting away from it, there’s a lot of negativity towards mods right now, but where is it coming from? Who is fueling this anti-mod attitude?

Looking at our survey, older drivers – those over 54 – have the least love for mods. They had a lot more hatred for pretty much every mod in the survey, especially when compared to drivers under 25.

For example, 53% of people over 54 hate modified exhausts, while roughly a third (32%) of under 25s feel the same way. In the same vein, car flags (29% vs. 11%), fluffy dice (43% vs. 18%) and underbody lights (33% vs. 19%) are all more disliked by over 54s. The only exception is spoilers, which are hated by a quarter of under 25s compared to just 19% of over 54s.

Petrol heads tend to be a bit more open to mods, though, as those who drive more often were less likely to hate on mods. Around three-quarters (72%) of daily drivers named at least one mod that they hate. But among those who only drive once a week, that number jumps to 84%. What can we say? We just like to stand out from the crowd!

But how do they impact your car’s value?

Okay, some mods aren’t everyone’s cup of tea. But before you start changing things up, keep a few things in mind, especially if you care about your car’s value. If you plan to sell your car in the future, you might want to hold off on making any major modifications.

We looked at our sales data and found that modding your car could cost you. On average, unmodified cars sell for about 97.1% of their valuation, while cars with at least one mod are sold for 94.4% of their valuation.[2]

On average, cars sold through our site go for £14,077. That means that modified cars sell for £380 less, on average. Keep in mind that this can vary depending on the type of mod and your specific situation. A loss of this amount could be a real blow, though. So, if you’re planning to modify your car, remember this before you up and sell.

Want to sell your car? Don’t get these modifications

What could be worse than reducing a car’s resale value? Making it completely unsellable, that’s what. When conducting our research, some people also said they would flat-out refuse to buy a car, regardless of its price, if it had any of these modifications:[1]

A huge 69% of drivers wouldn’t even entertain the possibility of buying a car if it had ‘wonky wheels’. Other personal design choices that don’t seem to be popular with buyers include, again, modified exhausts. Not only is it the most hated mod, but it’s also a deal breaker for almost two-thirds of UK drivers (65%). Well over half (56%) also said that underbody lights would be an instant no-no.

Spinning rims (53%), lowered suspension (64%), and novelty horns (58%) all also feature in the top 10 modifications to avoid if you’re looking to sell on.

The top 10 list is pretty much the same as it was four years ago. Wonky wheels are still the biggest turn-off for people buying a car, though there have been a few shifts in the rankings. For example, modified exhausts rose to second place over, bumping lowered suspension down to third. This really reaffirms the nation’s plummeting tolerance for this noisy add-on.

Novelty horns and underbody lights both rose slightly higher, too, while headlight eyelashes and novelty decals dropped down. The only new addition to the top 10 was tinted headlights (45%), pushing out custom paint jobs (44%), down by only 1%.

There is one key difference, though. Almost every mod on the list was considered a deal breaker by more buyers this year compared to 2020.

It might not be the best news for drivers who love to customise their ride, but it seems like the nation’s drivers are developing more and more of an anti-mod mentality. A huge 89% of those surveyed said there’s at least one modification that would stop them from buying a car – yikes!

Some drivers are a bit more open-minded, though. Based on our survey, people under 25 are the least likely to be put off by modifications. A fifth of this age group said that a modification wouldn’t stop them from buying a car, while only around a tenth of all other age ranges felt the same way.

About the data

[1] Drivers’ opinions on car modifications were collected by surveying 2,000 UK adults via YouGov. The survey ran on 3 July 2024 and respondents were selected at random. All data included in this page was sourced from this survey unless otherwise stated.

[2] The impact of modifications on a car’s sale price is based on internal Carwow sales data. We took the average percentage of the initial valuation that cars with and without mods sold for through Carwow in 2023 (94% and 97% respectively). We then took the average valuation for cars sold through Carwow between May and July 2024 – £14,077.

This figure was applied to the average percentage of the initial valuation received for cars with and without mods to determine how much they sell for (£13,288 and £13,668 respectively). We then took the difference between these to find the average loss as a result of mods – £380.