I might have found a bug, when trying to place an ic2 biofuel cell or a coalfuel cell in a diesel generator, it just spits out the empty cell and the biofuel or coalfuel just disappear. Using 2.75b
I'm also having like 3 seconds lag in my NEI search function with Gregtech installed. If I remove it or downgrade to 2.71, the lag is fixed. I'm pretty sure Greg is already investigating into this.