DougH ... I could'nt agree with you more!!!

As I now remember, I initially did use those plasic connectors on my friend's car, and a year later, she said she sometimes had trouble starting her car using her key switch. I then decided to remove all those plastic connectors and then soldered all connections.

While I never determined what caused those intermittant no-start situations, after soldering the connections everything was fine thereafter,and I was able to sleep better at night.

For critical circuits, soldering is the best way to go.