Has anyone out there tried to install aftermarket speaker spikes / cones (the large machined alum. / brass ones w/ floor discs) in place of the original spikes supplied with the B&W 600 Series 3 Floorstanders. What is involved - do you have to drill another hole - or does it fit into the threaded socket already on the base of the speakers? What kind of improvement in sound (if any) do you get with installing the really big spikes / cones (1 1/2" tall by 1 1/4" dia. - the ones I was considering). thanks.