If you are talking about using the K&N stock filter replacement, then you will probably be fine without the fuel processor even though you are adding V&H pipes. The air flow path on the stock airbox is like a twisted straw. Even with the lower restriction K&N filter, the air still has a godawful path to get to the intake. So you will notice very little if any extra air flow with the K&N filter because the restriction is actually in the airbox design. I still think the K&N filter is worth the money because it is reusable and the stock paper filter costs $30+ a pop. So it is economically sound to use it, just not performance wise.
Now if you are talking about going to an aftermarket airbox with K&N filter, you will definitely need the fuel processor when you add the V&H pipes because this removes the restrictions on both ends thus making your fuel/air mixture to lean.
'07 VN900 Classic
Horsepower is an illusion.
Torque is the source of all good things.