How much would it cost to upgrade an Audi A4 2008's lights to the signature LEDs feautured in the B8 models?

There are several headlights or kits that can be installed to your car for around 300 dollars.How much would it cost to upgrade an Audi A4 2008's lights to the signature LEDs feautured in the B8 models?The kid included with the bulbs costs anywhere from $200 to $400 depending on quality