Will purchasing this loom from newministuff.com negate the need for a line out processor/converter (i.e. AudioControl LC6i, JL Cleansweep, or RF 3Sixty.1)?

I understand this will require pulling the dash apart rather than tapping into the X9331 connector.

Will I not get full frequency sound? Do I need the signal processor's 'summing' function to obtain full spectrum sound?

Basically, I'm looking for the best option to add an Alpine PDX-5 to the standard (non-HiFi) system in an R57.

 

even without the loom you do not need "summing".

 

That is correct it plugs into the back of the HU and into the harness.

[quote=gdclnfn;2973611Will I not get full frequency sound? Do I need the signal processor's 'summing' function to obtain full spectrum sound

Basically, I'm looking for the best option to add an Alpine PDX-5 to the standard (non-HiFi) system in an R57.[/quote]
As you have the Non-HiFi system there is a roll off below 100Hz on the rear channels.

What you probably want to do is use the rear channel outputs to feed the front speakers and the front channel outputs to feed the rear speakers. This way you get the full spectrum tot eh speakers that are most able to handle it.
The ohter thing you willhave to do is replace teh speakers as the OEM speakers will not be able to handle the power of the PDX5

 

Thanks for the comments. I am hesitant do do the front/rear channel swap simply because I have bluetooth and rear parking sensors. That being the case, is a line out converter recommended in my situation? If so, any recommendations on which one? I was looking at a LC6i.

I should have been more clear...I will absolutely be replacing the speakers with (hopefully) Focal 165VRs up front and Focal 165CVXs for rears. Eventually looking to get a sub enclosure from urbanmini when it becomes available.