Del City and others, I'm sure, also sell a connector with the solder inside the terminal and a piece of shrink sleeve tube over it. Slip it on the sripped end of the wire and hit it with your heat gun, the solder melts and the shrink sleeve shrinks!!! Works great and holds tight. I use either these or solder type connectors with a QUALITY small tip soldering iron and shrink sleeve over the terminal. Also, don't forget to use a bunch of tie wraps, and anything that has a possibility of being pulled away from it's connection should have a strain relief on it.... On multiple wire looms, I also like to use the waxed string and convuluted tubing over the wires along with plenty of rubber insulated clamps to hold the loom. Takes time and costs a bit more, but quality usually does.......