Ok here is the update. So far I must have put around 200 hours of playtime through these speakers since the modifications. They are now fully run in. Below are my comments…
UPSIDES:-
A definite overall improvement in sound quality. More revealing than the unmodified original Beolab 6000. When listening to well recorded music, and connected to a Beosound 3000 Hifi unit via an offboard DAC, you are presented with a beautifully holographic 3D soundstage. The walls of my living room vanish, and I hear sounds coming from outside the boundaries of the speakers, even extending to past the front wall. I also notice that the these speakers like to go significantly louder without distress ((bearing in mind that I am using home-made Kimber interconnects between the speakers and the Beosound 3000 unit)).
DOWNSIDES:-
Speakers take a while to warm up. Immediately after being switched on from cold; the sound is a bit hollow, pinched and lacking in bass. However; these shortcomings gradually go away after the the first hour of playtime.
IMPORTANT NOTE…. I used the wrong size bass reflex tube. Needed to swap it for a larger size (2cm diameter hole).