I have the combo amp n sub installed in my E60, sounds great for the money and gives a much needed boost to the stock system.

I installed the amp sub combo in my avalon myself. But didn't take the risk to install it in my E60. Took it down to a car audio shop and had them install it. The location is rear back of the trunk on the driver side. Close to where the small stock amp is. I didn't ask too many questions as to how or where they hooked up to. The installation is clean and it sounds great wit my dynavin head unit. They mentioned they had to install something to seperate hi's n lo's... idk.. ill take pics and ask what they did. Ill check back in.