Is this plug a direct replacement for my car's original plugs?

Only if your engine specifies the IFR6T11 or an equivalent with the same 14 mm thread, 19 mm reach and heat range 6. Cross-check the number in your owner's manual or on the old plug before buying.

Do I need to gap it before installing?

It comes preset at 1.1 mm (0.044 in). Check the gap with a wire gauge and adjust only if needed, using care because the iridium tip is fragile.

How often should iridium plugs be changed?

Follow the manufacturer's interval, which on many iridium-equipped engines runs to around 60,000 to 100,000 miles. They outlast copper plugs by a wide margin.

Can I mix this plug with a different brand in the same engine?

It is best to use one matching set. Mixing heat ranges or brands can cause uneven running and makes diagnosis harder.

What tools do I need to install it?

A 5/8 inch (16 mm) spark plug socket, a torque wrench and dielectric grease for the boot. Torque to the figure in your service manual rather than guessing.