Hi everyone been browsing here for info for a while finally joined and have a question. Car is an e46 m3 Witt factory nav and Harmon kardon sound system option. I added a kicker dx5001 amp and a alpine type r (previous gen) sub In a sealed box in the trunk.

I spliced into the factory wiring from the head unit 'before' the Hk amp according to a website and several links as the suggested method. From there I connected to a Kicker zisl (think that's the name) that converts to RCAs into the amp. (Amp does not have speaker connections for input). The system has a balanced differential signal and the amp says it accepts it.

My question is do I use high or the low level setting on the button on the amp?

When I set it to low the sub pounds and it sounds way louder. If I set it to high it doesn't sound as loud but I obviously know that I can raise the gain.. Is that what I should do?

Any input is appreciated.