[Vidgamer]

Ok, I'm sure it pales in comparison to the $900 amp, but I got a JBL MS-2 and plugged it between the iPhone adapter and the AUX jack. Because of the goofy way BMW implements the iPhone integration, it allows this trick. What seemed like a bug is now a feature. ;-)

So, what is it? It's a DSP. It automatically equalizes and time- aligns. The imaging is much improved. But how good is it really?

I find it really does improve imaging, but the sound is a bit thin. I'm not sure it's audiophile quality by any means but it cost me $40, not $900. Better speakers would help too. The DSP can't fix everything. I'll try it for a while and see.