I've injected and done without - it was real tasty either way. You may want to try a small breast before the big day.
One other thing that I do that I've never seen mentioned - Just before I put the bird in, I turn off the flame and the gas tank. That way, if I have a boilover, there is less of a chance of fire. As soon as the bubbling calms down, I relight.
This did save me the one time I had a boilover - it was raining, and I set up in the doorway of my garage (yes, I know it was a stupid thing to do....). My turkey went fine. I put some potatoes in. I had them soaking in icewater and told my wife to dry them. Apparently, they weren't quite dry enough and boiled over. But my gas was off (and I did have plenty of fire extinguishing material around), so all I wound up with was a nasty oil slick on my driveway, which never quite came off.
So...turn off your gas and make sure what you're frying is dry!!
Mike