Inner-city driving is not always comfortable, and most of us need all the help we can get. It is possible to achieve in-car karma by fitting extras, but which ones are worth the investment?

Very few of the more expensive creature comforts actually increase the value of your

vehicle, but appropriate extras often make a car more saleable. Of course, some accessories are absolutely crucial, while others are nonsensical in a city.

Extras fitted in the factory are part of the company car tax equation, whereas dealer-installed items are exempt. There is also the after-market industry that provides cheap, cheerful and DIY options. So which extras make sense?

Air conditioning. Seems like an extravagance, but it offers instant relief for asthma, hay fever and other allergy sufferers, and instantly demists the windscreen in winter. Also indispensable in heatwave traffic jam scenarios. Alpinair in Stanmore can fit a system to almost any model, from a Mini upwards, in three days for pounds 850 to pounds 1,300. While 'air' as the trade call it, is essential on up-market limos, it's a novelty item on more ordinary cars so there's little chance of getting your money back, and it increases fuel consumption.

Power steering. Anyone who has ever attempted a 23-point turn in WC1 will appreciate the benefits of 'assisted' steering. It is increasingly standard on all but the smallest shopping hatches. It is not available on a Vauxhall Corsa 1.2i, but on a 1.4i LS the option costs pounds 357. Think of it is a bicep saver and an incentive for a future buyer.

Automatic gearbox. The lazy but oh-so-sensible way to make progress around our congested city. Not always avail-able on smaller cars but is expensive - pounds 920 on a mini. There is a ready resale market for small automatics within London. However, on medium-size cars like Escorts, or sports cars like Porsches, an auto-box can knock back values.

Leather. Vital for executive cars, including top of the range Rovers, Granadas and Senators. If you are 'into' leather, a company like Distinctive

Vehicle Interiors in SW18 will fully trim your saloon car for around pounds 1,000. Remember, though, it is cold in winter and sticky in summer, and it won't make your Nissan Micra any more desirable.

Music. All except the most basic models (Fiat Panda, Lada) or meanest manufacturers (Ferrari, Mercedes) have some form of in-car entertainment.

An all singing, all dancing CD system won't make a car more valuable, so when selling think about substituting it for a basic radio cassette. Neasden Electronics will do a basic swap for pounds 20 but within the world of hi-fi you can pay hundreds, or thousands of pounds, so shop around.

Alloy wheels. They only look good on cars for which they were designed, so Golf GTis, BMW 3-series and Mazda MX5s can look the poorer without them. On normal hatches and saloons they just look flash and the novelty wears off once you've clipped the kerb a few times.

Sunroof. Despite our climate, a hole in the roof is now a major factor in car valuations. A cheap solution is a 'pop-up' moon roof; however these should only be inflicted on old bangers. The London Sunroof Company offered a medium-size version for a Cavalier for pounds 97 plus VAT, or a more sophisticated sliding version for pounds 227.

Alarms. A must for the inner city, and many insurance companies insist on them. At best it will stop car thieves and discount your insurance prem-ium, at worst seriously annoy the neighbours. Shop around. A highly visible deterrent like a Carflow Longarm steering wheel clamp at pounds 49.50, is practical and will travel with you to your next car.

Tow bars. Not the most obvious of accessories but an effective defence against parking by touch practitioners. At the Edgware Trailer Centre, an pounds 80 tow bar would do the trick. However, future buyers may think you have been overloading the car by hauling a caravan around.

Easi-Park. A tiny plastic screen that sticks to the rear window and periscopes a bumper-eye view of just how close you are to the car behind when parking - pounds 5 or pounds 6 at the accessory shops we visited, put in perspective by the BMW Park Distance Control which costs a staggering pounds 320.

Mats. Rubber jobs are a pounds 1 or so from markets, Halfords and petrol stations. They protect the carpets and may even boost the value of your motor when sold.

Not every extra can be calculated in pure value for money terms. ABS brakes and airbags, which are expensive, might save your life. Fog lamps, heated mirrors, and headlight wash-wipes are also very practical. Fit what is appropriate and you can't go wrong.

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