You can buy them directly from Race Tech. The gold valve kits come with instructions for installation and recommendation for selecting the right shim combination for your weight and riding style etc. You can review the instructions via the "support" link on their web page.
Be aware that there are separate kits (and part numbers) for fork compression and rebound valve kits.
I bought mine from my local Race Tech shop but the itemized part numbers and prices were the same as shown on the Race Tech web site.