sub channel managed by DSP (3sixty.1) or amp?

I have an old 3sixty.1 I'm going to install on my truck's factory radio and I just purchased a 5 channel amp (Soundstream TN5.950D). My question is this, would I be better off using my 4 outputs from the factory radio and using the 3sixty to manage all 6 outputs or would I be better off just doing the 4 channels my stock radio has and do 4 inputs to the amp,then use its internal settings to manage the sub channel? I'm not one who's good at tuning, once I get it installed, I'll take it to a shop to have tuned by somebody who has a better ear for it.

Thanks for your advice