1. I would say invest in the cluch bell, clutch spring (in the sticky with the clutch bell, clutch spring upgrade on top of this forum) this will save you headaches later. the more teeth on the clutch the faster it is, the less teeth the quicker it is off the line but top end will be less.
2. Any 5 cell hump pack with a futaba connector will work, 1200mah is good, the higher the number the better the battery.
3. I would stick to plastic, its cheaper to replace when it brakes, aluminum will bend and the plastic will break that the aluminum is attached to.
4. hobbico hot shot 2 is a good ignitor, i have had mine for a couple of years and i am very happy with it.
5.