Also proper gauge wire for application, using ofc not CCA, proper fusing, sanding paint off grounds and then covering it with a conductive lubricant so it doesnt rust. All I can think of for now
Soldering all connection! Crimping as little as possible. Needless to say its a much stronger and more connective connection that won't come apart due to vibrations.
You guys at sonic are awesome, I always shop there. Keep up the good work!