Hey jeremyp ... you opened the eyes ...
I haven't heard anything about plug n play amplifiers.
I also checked e90forum and had a look at the E93 installation. Great and clean work.
I also have the basic audio, and I was looking for an easy upgrade solution keeping untouched the factory head unit.
IMO we should try the Blaupunkt pnp solution and stay away from dirty wire cutting. Later we can change speakers or add a sub. The sound quality will be much much better from that of the basic audio system.
But Im not sure whether there's an adapter for the new E89. I checked the product's pdf (
http://www.blaupunkt.com/de/download...ste_250407.pdf)
and says Z4 from 01/01 and on. Not sure what it means. Did U check for compatibility with the new E89 ?