Two identical lengths of wire of the same gauge will have the same resistance.
If your solder joints or the connections have enough resistance to matter, they are damaged and in need of repair.
Some have claimed the sensor side of the harness is used by the sensor in determining the difference between exhaust air and ambient air.
This would suggest otherwise:
http://www.ngksparkplugs.ca/tech-inf...en-sensors.cfm
It doesn't seem like that would play a very large role in the accuracy of your sensor. It would seem buildup on the inside/outside of the tip would be much more harmful here.
