Prob not safe, wire loom designed to supply current for a 55w bulb, the 100w will cause that cable to run hot.
There have been reports of people running up to 130w without any problems, one of those things that you are probably going to have to try yourself and be ready for the worst!!!!!
Ive seen people fitting 100w bulbs for many many without uprating the wiring and never heard of anyone having a problem. Its your car though but for how easy It is to fit a relay and better wiring i would add them just for peace of mind.
Serious? Ive heard loads of people that have had lenses melt, wiring to burn out. In some cases the front of the cars to set on fire. Your car thou, your choice
Has anyone heard of a megane melt its headlight fitting 100w bulbs? Might be more useful to help him decide.
Yeah, I have a set of 100w sat in the garage that I'm nervous about fitting. I'd love the nuts to put them or 130w in!