The TM AUG A1 is great, as long as you can get used to holding it.
I sold it because I found it uncomfortable to use.
The scope on the military is decent, I would go for the A2 model so you have the option of magnification 1.5x+, so good call there, OP.
I would go for a 3x scope if I were you, as the TM AUG is very accurate because of the barrel length.
Get an KA Phantom kit. They're good quality.
As for 400fps, all you need is a new spring.
However, there are always variables, best to aim for about 380 fps.
Hope I have been of help, Chris.
Feel free to PM me.
God is a /b/tard.