So, after three months of almost no real progress, time for a parts list. Please point out any flaws or recommend any good, cheaper alternatives:

Motors: 2x Argos 12V drill motors
Battery pack: Turnigy 2650mah 4S LiPo with 20C constant and 30C burst
Speed Controllers: 2x BotBitz TZ85a
Tx and RX: Spectrum DX5e (but also curious about trigger transmitters)
Armour: 10mm HDPE shell with 12mm HDPE bulkheads
Other: 125mm diameter RoboChallenge blue wheels
2 or 3mm aluminium to protect the battery

Sound reasonable?