I assume 100 watt is illegal but why 35 watt rather than 55 watt?

Do HIDs output more or less heat that conventional bulbs?

Ive had 35w and 55w. Imo the 55w isnt worth having over the 35. I saw no more visible light output, or very very little more. The only difference i found was that the 55w's take much longer to warmup.

Overall, hids produce less heat and are more effiecient than halogens. The heat that the hids do make is all from the arc.

What effect 100w Xenon H7 bulbs in standard pre-facelift projector headlamp?

 

 

Assuming the username is a Honda Blackbird? . 

 

You run the risk of pulling too much current draw through the OEM wiring and too much heat in the headlamp. 

 

As above. Also I've seen a couple of Vauxhalls where the owner had fitted 100W halogens, and melted the bulb holders out of the shells!

Assuming the username is a Honda Blackbird? . 

 

A million years and two broken wrists ago, yes. Sob!