What's annoying about Gascraft? It adds no worldgen, just a few innocuous socket modules that you wouldn't even know were there unless you were looking specifically for them (all the Engineer's toolbox modules look the same inside NEI). Its about as inoffensive a mod gets.
haha, i've heard stories about massive non-stop underground explosions. i think it has to do with using another terrain generation, though. i forget which. bop probably.