Morning Brian,
I wouldn't bother brining a turkey. We cooked a couple this past weekend and one came out perfect the other was a little dry. We did inject both of them. I would recommend staying away from the 4 minute per pound mark.
The idea behind brining is to prevent the bird from drying out, it will also add flavor. Since we injected the flavor was there for us. The second of the two turkeys we fried was very moist and tender, we cooked it for just under 3-1/2 minutes per pound. Another thing I have learned is that you need to stay with a smaller turkey if you want it to be well cooked throughout without drying. I have heard that anything beyond 15 pounds is too big. I am sure there are folks who might disagree, but I will stick to that rule. At work we had our annual turkey day last thursday and they had two twenty pounders and they didn't cook so completely. I am not a big turkey fan so I did not eat them anyway. The turduckin was good though.
As to brining, these birds are already juiced, so I would skip it.