I have added 6 1-1/8" air holes to the outer fire box casing of mine to add more air. Now I just need to put a raised coal rack in too. I hate hauling my big smoker around while we camp all summer so this smaller/more portable smoker makes perfect sense as long as I can get it to smoke meat well. So far, in stock form with lump charcoal, it has been nothing but a disappointment.
I know this thread is under "Charcoal Smokers" but if you get frustrated with heat control on this unit, consider getting one of these for it.