Well I'd say we qualify to earphone modders
There are a limited number of earbuds that you will be able use for this modification. Not only does the shell have to be able to be opened (and this is rare enough) but also the method of cable strain relief used must also be considered. Some manufacturers use glue, or metal clips, or knots etc. as strain relief. You do not want to do this mod and not recreate the strain relief or your buds won't be working for long. I belive most Sonys are glued shut, and you'll find it difficult to open them without damanging them in the process.
When we began adapting the Etymotic ER6i and Future Sonics FS1 to the iPhone cable we had tried literally dozens of mid and high end buds trying to find options that would work well (and long term) with a cable swap. Even today, we sometimes damage the FS1 driver during dissasembly and the Etymotics have a flex circuit board that is easily damaged.
I suggest a good electronics vice, very fine tip good quality soldering iron, tweezers. Good luck!
Brad
Ultimate Buds
www.ultimatebuds.com