Powerflex bushings are made from polyurethane so they flex far less than the squishy stock rubber bushings. Stiff bushings mean more precise alignment, better suspension control, and better steering feel.
Note that it is the nature of polyurethane to squeak eventually. Lubricating them periodically will reduce this tendency, but we will not take back any polyurethane suspension product because of noise.
#11 in the diagram
Set of two split bushings, plus a tube of lube.
Fits all 2002-2007 Subaru WRX and WRX STi.