Haven't done this in awhile, the last time I installed a car stereo, the # 1 song was Disco Duck, Rick Dees. Should I solder the wires directly to the speaker terminals, or use crimp on connectors which push on to the speaker terminals? If I use the connectors, is it good enough to crimp the connectors on to the wire, or should I solder them? Standard HU running 18 guage wire. Thanks!