I'm working on a 5 x engy team at the moment, mainly for 5 x flying machines, goggles, rocket launchers and Area 52 Dimensional Rippers. Not to mention 5 x those little bomb pets would look pretty cool.

The most powerful seaforium charge is this one:

http://www.wowhead.com/?spell=30547

Raw mats needed are 8 x fel iron ore (to make 4 fel iron bars), 1 x mote of fire, 2 x mote of earth. This will give you 2 charges.

They also open the doors in shattered halls, letting you bypass several mobs.