Full stock would be my choice, large battery right out of the box.
Second gun, the battery is a mini and in the foregrip.
Don't know anything about the third gun.
EDIT: As Crunchmeister said, the SD models are very restrictive when it comes to attachments/accessories. I'd personally buy the MP5A4 if I had the chance to, I've owned a TM MP5A5, and I didn't like the stock was more a machine pistol than a proper gun. My roommate had an A4 and it was very nice with the full stock on it.
Last edited by Moderate; April 28th, 2009 at 18:02..