The difference is the shock mounting hole. On the T2 arm you have 2 shock mounting holes, on the 008 you have 1 mounting hole. The hole on the 008 arm is in the exact middle of the two holes on the 007, so the shock would be mounted either 1mm more to the center of the car or 1mm more out compared to the 008 arm.
The 007 arm is also 1mm longer on the front pivot suspention pin. The 008 arm uses 2 pieces of 0,5mm spacers (1 in front and one on the back side of the arm) to adjust the front wheelbase, but if you remove the spacers then you can fit the 007 arm, except it will be placed as if you put both spacers in front of the 008 arm.
Sorry I don't have any image editing program on this computer so the images are a bit to large.
The 008 arm is on the left and 007 on the right:
http://home.no/hurrle/rc/007-008arms1.jpg
008 arm on top, 007 bottom:
http://home.no/hurrle/rc/007-008arms2.jpg