The IC2 Ex Team.
Firstly, thanks for a great mod that i've used from the very beginning.
Glass Fibre Cable used to cost a diamond per 8 pieces of GFC (if using silver as the added component). Now the recipe is 4 diamonds and 5 redstone to produce 9 energium dusts. then 2 energium dusts per piece of cable. That works out to be 9 pieces of GFC per 8 diamonds, or just under a diamond per piece)).
Now with the new kinetic Wind Gens that we have (that should be placed reasonably high up), GFC is really the only option to minamize EU loss.
Anyhow, someone maybe would like to look into a re-balance of GFC cost. 8 pieces per diamond is reasonable, I think! But, I'll leave it to you to decide.
Thanks for reading and all the work. Have a good one.