Why do some claim a tune is needed after a CAI??

[CanadaStang]

People tend to forget that just because you increase the air flow some that does not make it lean. The MAF is there for a reason. The increased airflow will still be measured and acounted for when creating the a/f mixture. Your point on the CAI's with the bend is a valid one.

The a/f may be goofed by the bend in the fenderwell intakes because the flow of the air is along the outside of the CAI pipe... or the side that faces the engine. The reason the design causes the car to run rich is because while air is filling the entire pipe, it is mostly concentrated along that engine side of the pipe. The MAF sensor in turn interperets this as more air coming in, and in turn the computer compensates for more air by adding more fuel. However, in reality, the same, or near the same amount of air is being pulled into the engine, it's just mostly concentrated on one side of the pipe.
Same air + more fuel = rich conditions. And this is a power robbing condition. The CAI with no bend shouldn't cause any issues.