beryllium is 1/3 lighter than aluminum yet 6x the specific stiffness of steel
IIRC, it outclasses Ti in that way - dunno re stress cracking but the newest Ti alloys are better than their reputation
the dust is highly toxic - ask Porsche who used them - briefly - on brake components of some race cars
might be fun to see if the German govt. allows Be in speakers - you can get away with putting toxic liquids in cables in Canada and importing them into the US though
