Hi - you need to remove the sub by undoing the screws and removing the wiring loom socket then lay the sub on its side on the boot floor. Alfa have already thought of changing the struts and you will find a partial cut-out on each side in the carpet on top of the turrets. Cut it around a bit more with a stanley knife to make a flap. You will then reveal a thick rubber packer inside which has to be pulled out - quite a struggle to remove! - then, hey presto - you will expose the top nut on the strut. There is an allen key socket in the top centre of the strut thread and with a ring spanner and allen key you can undo the nut and lower the strut.
Hope this didn't go on too long and was informative!!
