I use:
2x MFA motor (15:1) with 50mm wheels for drive
a 12ah sabretooth speed cotroler
lego pnumatics, with a deodrant can, or copper pipes for the cilinder
and 6mm hdpe for the body
and 1.5mm stainless steel for the armour
and I dont have a battery yet

but is there going to be an event? because if its going to the guildford event its getting quiet close