I upgraded by speakers
I went ahead and bit the bullet and bought the BSW Stage 1 package with the tool kit for my z3 2000.
First, the speakers are awesome but very pricey.
Second, the package I got was for the HK premium system but the Stage 1 package doesnt come with the mid range door speakers. I was upset to find out that I had to buy the rear speakers at an additional 150 and the mid ranges in the doors for 150.
Third, you do NOT have to buy their repair kit but its nice to have a kit. The kit looks cool but you can just as easily remove everything without it. The kit didnt come with the sockets that were needed for the kick panel speakers.
I am re-foaming my sub woofer. I will let you know how that goes.