K&N Filter: 2 ways you can use this upgrade. First there is a drop-in filter that replaces the stock paper filter using the stock airbox which should get 2-3HP. The second upgrade uses a large cone filter that replaces the stock filter and airbox. The cone setup will require a 6x9 K&N cone filter, 3inch 45-degree PVC pipe, 3x3 inch rubber PVC pipe connector and a Honda PCV grommet. The picture above is the complete assembly put together but without the hole drilled in the middle of the PVC pipe for the grommet that holds the IAT sensor. The cone setup should provide a 4-5HP gain. The drop in filter retails for $35-40.00 and is available at most PEPBOYS autoparts stores and JEG's high performance mail order. Depending on where you go for parts the cone setup will cost you $60-70.00. The PVC pipe and rubber connector can be found at a hardware\pluming supply store. The Honda PCV grommet and cone filter are available from PEPBOYS.