Okay, I have recieved an e-mail from Giro. Staright from the horses mouth.
"Hey there Lyndon,
To answer your question, we strongly advise you not to drill holes in your helmet. Here is why. All Giro helmets are engineered using an impact mold design, where the plastic shell is injected into a mod, as well as the foam inserts. In this process, The plastics are solidified with pressure in all directions, giving the helmet stiffness and impact resistance. Once the rigidity of the helmet is breached, such as a hole, crack, or dent, the entire structure is compromised. It is not safe to put holes, paint, or sand down your helmet.
Our helmets are made for a single (1) impact. We advise you replace your helmet after this happens. If you have any more questions, feel free to reach me at this email. My name is Erik, and I am more than happy to assist you.
Thanks for choosing Giro.
Seems to me he says drilling holes in a helmet isnt a very bright thing to do? But hey, I could be wrong.
With my most sincere regards,
"Skiing should be more like other "action" sports in which there are many different styles and ways of going about it all in which are accepted..make sense?" -powfoka