Originally Posted by 370Z Purist

All the improvements would most improve air flow. Zero welds means less turbulence, because the entire inside of the tube is smooth at a macromolecular level. Longer straight tubing reduces misreading at the MAF, and will deliver more accurate, precise voltage output, which prevents the ECU from tripping balls because the airflow changes. Straighter, longer tubing, again, reduces turbulence. Shorter overall length means less travel from filter to throttle body, lowering the resistance of the air to movement. It's easier to suck from a straw that's a foot long than 10 feet long (fun experiment, btw). I know what a bend radius is, but I'm not sure what "open radius bends" are. What I'm guessing is that the bends are less extreme, again smoothing airflow and reducing turbulence.

Basically speaking, smoother, more laminar airflow = faster moving, smoother, more consistent airflow. This means the MAF reads better and more accurately, and also provides a good intake charge into the plenum. All this means more horsepower across the band, although I'd imagine the biggest gains are at mid to high RPMs where faster moving air normally causes more problems especially with the stock intake tubing.

Of course, I'm only an engineering student, so these are the most likely improvements, but the actual engineer developing the intakes probably has more reasons which might also be more complicated.

I can't remember if welding or mandrel bending is cheaper overall.