O opted away from soldering 100%, after some research I have gone toward 100% crimped connectors, my harness is essentially 100% new with all new wiring, for places where i needed to make y conenctions or multi connections, I am using nice barrel type butt crimps and heat shrink. I must have $300 in crimps and wire from that website. my original plan was to mount hte ecu in the engine bay, however I am going to reinstall it back under the dash, I will end up spending some more money on bulkhead connectors to make it removable