I thought the scariest part of the mod job was flashing the firmware...I always worry when doing that.
I'd recommend just cutting the traces to the motor and soldering wire in to change the polarity...then you don't need to deal with desoldering or disconnecting the drive's rubber band thingy. (Actually, I couldn't figure out how to remove that PCB and didn't want to break it...I think you need to shave down the PCB a little to get over motor's plastic holder.) Just make sure the traces are fully cut and then insulate with some hot glue.
To make the drive sturdy, I guesstimated where the screw holes were and used a phillips screwdriver to drill the hole in the caddy plastic.
Then used hot glue to attach the faceplate.
All in all, it maybe sits back a quarter inch.
My next project is to mount a 616 in there with the faceplate and everything, but I need to move the power/eject buttons

Also, most of the tut's say you may need to switch TRin & TRout...it won't do any damage if you find out you have to(the tray will eject when you power off).