Does this come with the mounting bracket, or just the glass?

Just the glass lens itself. The bracket and housing stay on your vehicle — you're swapping out only the reflective surface and heating element.

Will the heating element work immediately, or do I need to wire anything?

The heating element is pre-integrated into the lens. As long as your mirror housing connector is intact, power flows through to the glass the moment you install it. No additional wiring.

Is there a break-in period or special prep before I use the heater?

Run a test fit first to confirm the lens seats fully in the housing. Once installed, you can use the heater immediately — no cure time or prep work needed.