[fmorelli]

Once you have the new amp in play, whatever BMW does with the center channel becomes moot. :-)

Maceij @ bimmertech agreed with me - that the center channel should be repurposed to solve the bridging issue on the Z4. Hopefully the above photos help. The only trick is that you need to aquire a connector. One way to do it is to clip it off your stock center channel speaker (one can always resolder that on). I'm just adverse to cutting the factory wiring harness itself.

BTW I don't know that I know that much more ... I'm pushing my way through this bit by bit, and thankfully others here are providing some information and help. A high tide raises all boats.

Filippo