Do these sensors plug directly into the factory connectors?

Yes. These are built to factory spec and connect to the OEM wiring harness without adapters or modifications.

What happens if I only replace one sensor instead of both?

Your engine computer monitors both sides. Installing a new sensor on one side only can trigger imbalance codes and inconsistent fuel trim readings. The pair replacement ensures matched performance across both banks.

Will I need any special tools to install these?

Standard oxygen sensor socket or wrench fits the sensor body. No exotic tools required, though a lift or ramps makes underbody access easier.