Long time viewer, first time poster....
I have scoured the Suspension and Handling area, but am not able to figure out if an 2009-10 Forester rear sway bar is in any way different than previous years bars.
In particular, I would like to upgrade the stock rear sway bar (13mm? hollow?) with something stiffer. My take-away from the posts is that an early model WRX rear bar (non-STi) will fit, and, that a 17-19mm bar will flatten my handling somewhat without introducing excessive oversteer (and would also allow me to use the stock dogbone endlinks).
To be clear, I'm not really looking for ultimate handling

--just a more balanced car (over v. understeer) with a bit more "snap". I have found a source for a [20mm bar for 1993-2003 Impreza] and also a [20mm bar for 2004-2007 Impreza]. It seems like I need the 93-03 part. However is that size too big for the stock mounting and endlink hardware? Should I keep looking for a 17mm?
Sorry this post is a bit vague; I'm simply not finding anything definitive for such a new model car. Any help is appreciated.