CAI: No. Try a warm air intake instead. CAI is good for increasing top-end power, and if you drive like a jerk then the extra air flow could help fuel economy. WAI is more likely to work for someone who cares about fuel economy.
Vortex doohickey: Never. There is not one shred of credible evidence that one of those has ever worked on anything.
hunterhound 
Threaded Mode
