So.. lets say you don't want to spend the $35 for the tamiya screw kit. Here's what you need to buy:

• M3 x 8 Button - 8
• M3 x 10 Button - 39
• M3 x 12 Button - 7
• M3 x 15 Button - 4
• M3 x 18 Button - 2
• M3 x 10 Flat - 7

Then Tamiya specific screws.

• M3 x 18 Step - 2
• M3 x 14 Step - 10

These are both available from Tamiya as low friction screws. I beleive they are "Tamiya specific."