Step 4: Cut speaker grills and prep all the small bits.
Use whatever means are convenient to cut it down to about this size (just bigger than the mounting circle for the speakers); I mounted the grill on a block of wood and used a hole saw, but cutting it off with a pair of snips would likely work almost as well. Stick the speakers back in them when you're done.
Next, make sure all the control buttons work. (I did this post-soldering, but it makes more sense to do it now). I found that, although the logic board is held in with two screws, the two buttons closest to the USB port wouldn't work without the pressure of the exterior housing pressing the board down. I applied a little bit of super glue between the USB port and the plastic and held it down firmly (using ream-and-key technology) while it dried to ensure that the board was firm against its housing.
Take your exacto knife and slit the two foam pads down the middle, vertically, slightly more than half way. There are lots of fancy ways to cut foam cleanly, but this isn't going to be seen so short repetitive strokes worked fine.
Finally, If you're using shrink tubing, stick it on the speaker wires on either side now.