Using any type of injection for turkey (or any meat) will help add moisture and flavor, even if you don’t cure the turkey, but what also really helps in keeping a moister final product is adding salt and phosphates. The recipe I linked to above does call for adding phosphate as there is none in the base cure. If you inject another seasoning, butter, spices, etc. it would also help retain more moisture by adding phosphate to any injection solution. Some seasonings and marinades, like our favorite injection seasoning Butter Flavored Seasoning, will already contain phosphates, so do double check the ingredients statement to verify if phosphates are already added. But long story short, if you are really looking to retain the most moisture as possible in your final cooked product, do add something like Cold Phosphate to your marinade/injections, if it doesn’t already contain phosphates.