I got my HMF from Ebay as well. But I went ahead and got the Dynojet kit and K&N to go along with it, and am running a DJ170. I don't know how much difference you will notice between the 165 and 170...but with the other mods that I added at the same time, it made a WORLD of difference. I couldn't believe how much that it woke my bike up. If money is no object (which it isnt when it comes to our bikes), I would highly suggest to compete the package with the DJ kit and K&N.