Includes parts needed for either Stage 1 or Stage 2.
Order air filter seperately (see related items).
STAGE 1 is for mildly tuned machines using the stock airbox, with stock or K&N filter #KA-6589.
STAGE 2 is for mildly tuned machines using stock airbox with lid removed. K&N filter #KA-6589.
Both stages may be used with a good aftermarket exhaust.