What solder to use on basic automotive wiring?

I read the marine articles and have read other info in the past. Soldering after crimping has 2 advantages - backup in case your crimp wasn't tight and corrosion protection. Circuit board copper traces are usually "tinned" w/ solder to prevent corrosion, as is some stranded copper wire during manufacture. If a crimp is very tight and perfect, it can be "oxygen free", thus the interface between the copper won't corrode (turn green, copper oxide). I know the "fused" (welded?) ALT wire junction under my dash wasn't tight enough because mine was green in both A's, and many have found those melted from corrosion. The main downside of solder is it stiffens the wire so it may not flex enough and break, if in a place were it gets tugged.