Followed someone's advice and had a look on the scoobynet bulletin board. Here's what they say about headlights...
One of the main problems with the standard Impreza, is that the headlights are extremely poor for the levels of performance offered by the car. Traditionally, owners wishing to increase the output of their headlamps would fit higher wattage bulbs (illegal in the UK!). Unfortunately, in some sort of cost/weight saving frenzy, Subaru seem to have equipped the Impreza with plastic reflectors and the absolute minimum thickness of wiring necessary to drive the standard headlights. There have been numerous cases reported of the wiring getting very hot, and in some cases reflectors and wiring melting with higher wattage bulbs fitted. Some owners have been running the higher wattage bulbs without problem for several years. Fit these types of bulbs at your own risk!
Another option are high performance Xenon bulbs, which claim to offer 30% brighter light, for the same power. A growing number of owners are fitting these type of bulbs, including myself, and they do make a noticeable difference. The light produced is noticeably brighter (whiter), especially off-beam, when you can pick up a lot more detail at the edge of the road. As long as you are not expecting them to turn darkness into daylight, then they are a worthwhile improvement. These Xenon bulbs are available from a number of sources. PIAA have also introduced a range of high-efficiency bulbs, with e.g. the 80w bulb producing equivalent light to a 130w conventional bulbs. These are very expensive though!
So - fit the big bulbs and your EVO might not blow up, but the wiring might burst into flames. I think I'll buy some Xenons...
