My two pence worth chaps, the earth cable will simply NOT carry the extra current that the 100w bulbs draw let alone the 130w ones.
It will also put extra load on the switch, but the cable size is the problem area.
It will heat up quite significantly as the cable struggles to carry the load, it then cools very quicky when the current is switched off.
Multiple this a few hundred time and the cable will "work harden", the cable then becomes very brittle and is VERY liable to break.
The nett result will then be a complete and utter head light failure or in Laymans terms..............in the shit!
Yes, people might have used 100/130w bulbs, but have you checked the cables to see how brittle they are?
Personal choice then, but I would'nt even consider it
Personally I would recommend the PIAA Super White bulbs, 55w bulbs that give the light output of a 110w bulbs (I think?) But, without ANY risk of causing damage to either the loom or the switch.
BTBR