20k from an Assault mission. Each mission has 1 specific piece you can try for (from each of the 3 sets available.) Points are not shared between Assault missions. Since ID Tags only refresh one a day, you should choose in advance which pieces you want in which order, and focus on that particular mission. You can look up what each mission offers by talking to the individual people.
Edit: Apparently the more you do one particular mission (without doing others) the less Assault Points you are rewarded. So focusing on 1 area's mission might not be such a good idea at the moment. Been told more missions (and maybe storyline) opens up when you complete all 5 areas.
Edited, Wed Apr 26 07:36:08 2006 by FFTessei