Got a set from another ebay vendor. Front was a 10 minute job max. Rear was longer as you need to remove the rear seats and there isn't a huge amount of room to work back there as the holes you have to pass the bar ends through into the trunk are kinda tight. Fit on the front one was perfect, rear was decent, little bit of fiddling.
This site has an excellent step by step description of how to do the rear one. You'll need a torque wrench to do front or rear, very important.
http://www.oakos.com/wrx/installs/RSTB/index.htm
Difference in steering response was felt immediately, quicker turn-in. Car feels tighter under hard cornering. Well worth the $80.00 total I paid for both bars.
Also installed the STi titanium shift knob, slightly smaller diameter than the leather one that came with the car, but it really dresses up the look of the interior in my eyes. Would be nice if someone does a leather shift boot to replace the cheezy vinyl one.