I have a 03 mustang v6 with mach 460 sound system and i want to add an aftermarket stereo speakers and sub, i have a pioneer avh 275dvd, 4x infinity kappa 6x9 a 4 channel amp for speakers and a soundqubed sub with its amp, should i just connect everything asside from the mach system or whata the best thing that i can do? Without removing factory harnesses/wiring and just leaving it there