CE is a
GREAT way to kill BFRs. It takes quite a few, but if a BFR hits a minfield, running, they go boom 8/10 times.
In your in a tank, get your driver to ram you straight into one(the back side works better) and your guns are insdie the shield. Raming the 100s up a BFRs ass will generally get you the kill.
Also, a good way not to die from a BFR is to make sure your not what it is.
I famous global: "Don't footzerg the AI BFRs guys. Thats just silly."
BFRs are VERY helpless againist lots of air, or air period if it doesn't have AA.