With the direct fit, the harness is attached so you unplug one and plug in the new one. The universal requires you to use a splice kit to join the 4 wires. It's straight forward and hard to mess up unless your're doing it unnder the car in poor light. I'd remove the old sensor and work with it somewhere where you can sit down so you can be sure each "bullet" splice is secure. Also, some vendors have the wrong # listing for the 96 850 which I found out the hard way and typically there is a no return policy on electrical parts once installed. Make sure to check and double check the #'s to make sure you have the correct one.