Yes, with adding the K&N to the stock box you will increase airflow and have to add more fuel. Instead of getting a jet kit, consider doing the "Scar" method yourself. K&N added to a stock airbox should take one .02" shim to shim the needle up. Your A/F screw is most likely set at 2&1/2 turns at the factory, so you shouldn't have to mess with that. Search the threads on this forum talking about re-jetting and you'll find info. on this method, or got to www.vtxoa.com and look at the thread on the 1300 riders board labeled "Carb Tuning Simplified." This is much cheaper than buying a jet kit, and works well for most out there that have done it. Pretty easy job to do as well. Just a thought.