those are not stock banshee shocks.  if it fits a stock banshee it is a little short and untuned including the spring. 

works lists the price clearly at around 500 and they are tuned and the correct length. 

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if somebody who has mounted this and measured the castor on the front wheels i would like to banter.  but its clear to me that it has a negative impact on handling unless you know what your doing.  suzuki built the fastest flattrack frame in the world.  ignoring angle of geometry is a mistake. 

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believing you will save money is the only good thing.