I have an '07 Fatboy with V&H Short Shot Staggered pipes and I have been wanting to change over to the K&N HD-1499 OEM filter which K&N tells me I can and the o2 sensors will adjust for it without remapping. Is this the case since I am only changing the filter and not the actual breather casing with the original opening?

 

You will get several different answers on this one, but I have read that if you change both the exhaust and AC, you will need a map. Looks as if you have already done the exhaust thing, now the AC will probably warrant one.

 

If you just change the air filter element, from stock to the K&N version, it will not measurably alter your air/fuel ratio. It also will not measurably improve your performance. You will not have to do any remapping.
If you change the complete air intake, from the, stock setup to a stage 1 version, such as a SE air filter system or equivalent, this will alter you air/fuel ratio and you will have to do do a remap.
Tom