mitsubishi galant 2004

So I've run into quite the dilemma with my 2004 Mitsubishi Galant. I recently purchased and had new DSC65 6.5 inch and 6x9 KICKER brand speaker's installed which are working just fine, and also a Pioneer MVH-X370BT stereo for aux cord and BT input. The big problem that my mechanic has run into...