Just wanted to put some of this data into some graphs for you guys... seems like it isn't relevant unless we can review it.
This graph show simply how many people (who reposnded to this thread) have had a BHG and how many have not. (Out of about 90 people, 43% said yes and 57% said no)
Here are the results for people who said yes and no to having a BHG and at what Miles they have or the BHG occurred.
Here's what it looks like when you put the data together. Unfortunately there is no zone where the G2 won't blow a head gasket however if your car has over 200K on it I would say the chances are slim providing you continue to over-service the cooling system.
EDIT: Don't want to be cocky here, however there is obviously a floor in the design of the C32A when it comes to the heads mating to the block.
I can only think of a couple of cases where a G1 has reported a BHG and of those only one or two were confirmed. Sure they will blow a head gasket like every other car if it is over heated where the heads warp etc, but they don't seem to do it just because they feel like it as with the G2's. (Are there any theories on why they blow headgaskets at such a high rate?)