I have a Pioneer DEH-P8600MP
http://www.carreview.com/cat/car-audio/cd-receivers/pioneer/PRD_323446_2861crx.aspx
And an Alpine MRP-M450
http://www.crutchfield.com/S-ni9LOZavOkk/App/Product/Item/Main.aspx?i=500MRPM450
Should I use the headunit crossover or the amp crossover???
If I should...