Chargriller smokin' champ

[Harrisal21]

I have a chargriller smokin' champ and was looking at a few mods to do to get better/even temp control in the CC. I'm looking at installing tuning plates. I was also looking at extending the stack about 18 inches. My question is if tuning plates are installed is it pointless to extend the stack?

 

[Chasdev]

Two different animals, the plates try to move the heat from the firebox end down towards the opposite end in an effort to reduce the hot spot at the firebox opening.
Extending the exhaust stack changes the rate of airflow through the cooker and may make fire management easier.