If you cook it cook it right it will be plenty moist without injecting. Two reasons a brisket gets dry under cooking and over cooking, in either case an injection won't help you. I cook my briskets at 300 4 hrs wrap in BP until Probe tender, remove from the pit and let it sit until the internal temp is into the 150's.
I never met a Cow that I didn't like with a little Salt & Pepper! Certified PORK-A-HOLIC