I asked this same question a few weeks back. From personal experience, using 100W90 bulbs is fine. No problems with the lenses or wiring. My local rally outfit has also used 130W bulbs with no problems, but I'd be worried about either the wiring or the lens assembly melting at this rating.
If I was you, I'd stick with 100W90's. Technically, these are still illegal in the UK, but you can now get bulbs which are E marked (European Approval). Presumably this means that they are legal in some parts of the EU. If you do change the bulbs, just make sure that your lights are properly aligned, so you aren't unintentionally dazzling people.
I've found that these bulbs give a reasonable improvement in light output, without causing problems for oncoming drivers. For the bulbs I have, the spread and reach of the light seems to be better without actually increasing in brightness that much.
As I think I have mentioned before on some long-lost thread similar to this, my car from tha land of the rising sun fitted with the 80/80w PIAAs like Zippy has, when they (eventually) blew I replaced each in turn with 100w jobbies from Halfords (~£6 each). To be brutally honest there isn't much between them, especially considering the price difference. I did try a 'normal' 60w but found it significantly poorer in output and spread.
Many have complained about the lights on the early (and later I gather) Lancers but I really cannot fault them.