Fancy lights are better for drivers who cover long distances, since for short trips the conventional halogen lights still fitted to many cars are fine. Halogen lamps are also low cost, reliable and easy to change.
On the other hand, high-intensity xenon lights offer some of the best illumination that money can buy. LEDS are also very energy efficient but they can heat up neighbouring assemblies which makes them unsuitable for some cars.
So the short answer is that conversions can be done but they are often extremely complicated and expensive.
In both cases it is not just a case of changing bulbs but rather the entire lighting installation.
Light systems are marketed as safety aids but if not fitted properly they can dazzle other road users and even damage a vehicle.
Switching from one type to another is also not a do-it-yourself job. It calls for skills that the average driver or even home mechanic will not have.
"Work on light systems should definitely be left to professionals," said expert Christian Heinz from the Tuv type approval agency. Prices vary widely for retrofit conversion kits and some may be illegal since they do not comply with standards.
Fitting xenon bulbs to an existing halogen set-up can be downright dangerous. Incompatible bulbs can generate excessive heat and even melt wiring owing to excess current.
The xenon bulbs will not match the optical features of the lamp designed for halogen either and glare will result.
Aftermarket light kits can also sometimes be illegal and if used on the road may cause an accident which will invalidate the warranty and not be covered by the vehicle's regular insurance policy.
"People should carefully weigh up the pros and cons of retrofitting more powerful headlamps," said Heinz.
Factory-approved conversion kits from the vehicle manufacturer are a good bet and there are also trustworthy companies on the Internet offering changeover kits made up of original parts.
