I got and installed a Perrin pulley despite what some people say that you might have a problem. After several weeks of driving around and listening to the engine I can say that there are no noticible problems yet. My car revs faster and shifts even better. Get it if you want your car to pull more like a STI. I ordered mine from the great folks at
http://www.jscspeed.com/wrx/engine/p...ank_pulley.htm who shipped it to me very promptly.