This is, in my experience, the best barrel on the market for Polar Stars under ($100).
The ability to adjust air flow with an FCU is why this is perfect for the Fusion Engine system. My friend has one in his, and it makes my P* look like a stock JG, with either my ER hopped Prommy 550mm 6.03 or Madbull 650mm 6.01 with a Maple Leaf bucking.
We have the same nozzle and comparable FCU settings, and while my plastic will get downrange a split second faster, his maintains ridiculous accuracy and consistency while reaching out about as far as my DMR.
If you own a P*, you owe it to yourself to get one of these. I cannot speak for its performance as compared to PDI, but its the best I have witnessed.
Turns your P* into a tack-driver
Increases range at a lower fps
Less efficient on air