I'll 2nd this... I soldered connections in may early rally cars but stopped after they started breaking right where Kit says. If you solder connections, you have to solidly support the wires a few inches past the end of the solder to prevent this problem.
BTW, the conductivity of solder is right around 1/10th that of copper.
Something you notice but don't really put together in your head (heat affected metal). I guess I'll just be happy with my press die and shrink tubing from now on! :)
