[Jaydee]

Have been involved with light aircraft for a few years, soldering has been discussed many times. If you solder a terminal that goes onto a solid mount, like gauges or whatever, the strain on the solder will eventually crack the joint. Whereas, crimping allows flex, especially with the proper crimper, then the terminal plastic sleeve will support on the wire insulation. But solder joining a wire together, with shrink tubing, then taped to the rest of the wiring, won't crack the solder as there is no stress. If anything, if you crimp it, and moisture gets into, you'll get resistance, overheating etc.
JD