Very intersted in hearing how the long term review on this is going. For $40 it's well worth a shot, although i couldnt find any on the ms3 forums for cheaper than $85 + shipping.The 2010+ MS3 rear sway bar needs added to this list. It is a 26mm solid bar. Use Prothane or Energy Suspension urethane bushings with "B" brackets. You can get either with or without grease fittings. Move the factory MS3 location collars inboard some to clear new bushings. Just tap them with a mallet and a screwdriver or punch. They will move with little force. They will stay in place, but you can put a hose clamp beside them if you are worried.
These bars can be had used for as little as $40. Look at online salvage sites or Mazda forums.
Of course the many available aftermarket MS3 bars will work too. Some are HUGE. [headbang]