Injections basically serve two purposes,
1. Increase/maintain moisture by way of phosphate (and additional liquid, of course)
2. Allow for additional flavor components so as to create an edge at the judging table.
I believe a well selected brisket, simply smoked with a minimum of fuss will equal anything I've injected. Maybe a little au jus from the FTC juices over the sliced meat...I'm good to go.