Erm regarding the lag/crashing it could have been from my house as I have been offline for 5 days while I moved to a new home and just went on to see one of my transport pipes had been left on spewing cobble everywhere from my recycler there was about 15 20 stacks on the floor not sure if this was the cause if it was I am really sorry I didn't even know it was on, I have picked them all up now and destroyed the cobble feed.
Not wanting to have a moan
p (and I'm sure most people are unaware of potential problems with BC pipes)) but this is why everyone should use RedPower Pneumatic tubes. No overflowing & no cobble produced when there's not a valid open inventory, along with a much better routing system.
Additionally, if someone is using a world anchor/someone nearby has a world anchor, there will not be any overflow due to pipes leading through unloaded chunks. RP will just detect there's no inventory connected, and nothing will happen, whereas BC pipes will happily pipe the items through, leading to a massive pile of entities laying on the floor!
NoLagg should have an option to group similar entities into stacks, removing some of the entity lag. Additionally, it can delete entities if the amount surpasses the specified limit, so if a cobble machine explodes/overflows, then it will start removing entities after 100 have appeared, for example.