Originally Posted by jayblz20
I'm trying to install a new head unit, amp, subs ect. in my 2011 legacy 2.5i limited with HK. I am having trouble figuring out all the parts Ill need in order to keep my HK and my controls on the steering wheel working properly. Can anyone help? Do i need to find an interface, or a special harness?
I'm guessing your OEM HU is the US model with "PE605U6" printed on the front. Correct?
As a starting point, see this guide
Are you going to remove and replace your OEM h/k amp? If so, you can go with a 20-pin harness with plain (or no) speaker wires instead of male RCA plugs. And you won't need the h/k amp trigger lead on the 24-pin aux harness. If you want to reuse your car's factory speaker wires (nothing wrong with doing that), you can obtain harnesses to connect to the factory speaker harnesses (2 of the ones that are currently plugged into your h/k amp). See this post
On the other hand, if you want to retain the h/k amp, and only want to add a new amp for subwoofers, get the parts listed in the 1st guide above to connect your new HU's main speaker line outs (RCA jacks) to the h/k amp. Then run your new subwoofer amp from your new HU's subwoofer line outs (RCAs).