This is the number of the K&Ns I'm using now. I was trying to find the original XF paper type just so we could do a DYNO run to find out the diiference adding the K&Ns would make. I have also now added the 74mm TB since, I would have to remove it and put the 68mm back on so we could make a run with it too. I hate to have to buy a set of filters I'm not going to use but once. I was hoping to find a set that wasn't too dirty just to make a run on the DYNO.