Mine are the Clifford shorties. If I ever need to adjust the box NOW, I'll have to remove them, because they block the adjustment screw. The power box is taller there so the screw would interfere with the headers, so I'd have to modify them. I've been thinking about going back to the manifold anyway, because believe it or not, not only can I really not tell much of a difference in power now that I've had them on a while, but I'm not really crazy about how they made the exhaust sound.