Found this when looking for something else today. Its a standard warning on a US wheel site.
WARNING! Tire Pressure Monitoring System
Your vehicle is equipped with a tire pressure monitoring system that requires a sensor to be installed in the tire and wheel assembly for proper operation.
The original sensors from your original wheels can be used or you may purchase sensors from Tire Rack.
Your system includes:
315MHZ TIRE PRESSURE SENSOR
$260.00 for a quantity of 4
Total Price: $260.00
Additional Information
If you purchase a Tire & Wheel Package when you buy new sensors, the sensors will be installed on the wheels at no additional charge. Otherwise, you will have to arrange for installation by a trained technician after your new wheels are shipped to you. Tire Rack's Recommended Installers are available to help you with your installation needs and can be selected by ZIP Code in the shopping cart.
Once installed, you will need to read your vehicle's owner's manual to review the proper procedure for allowing your vehicle to "recognize" the new sensors.