Whiteline makes this front sway bar specifically for the WRX wagon. The narrow front track of the wagon also demands a narrower front sway bar. If you put a sedan sway bar on, it will fit, but the end links will be subjected to some unnatural angles and may be damaged. A wagon-specific bar will work as Subaru intended.
The bar is 22mm in diameter, and is three-way adjustable.
Fits all 2002-2007 Subaru WRX wagon. Saab 9-2X, too!