I got to try mine out today, and I love it. First off, you will need a small 1/4" pipe if you do not use the regulator on your air compressor.
I am using LBT Commercial Blue Lube, very high temp made for clean lubing in a commercial operation. This cause me to have to continually increase the screw pressure on the lube or I would not get a full groove each time. I installed this unit and put teflon tape on each joint before connection. I found with the correct operating temperature that I only needed 25 psi to get good even lubrication.
The parts were made well, the part that fits on top of the Star sizer appears to be made out of aluminum. The O-ring that fits into the stock Star cap appears to do the job. I do get some air seepage from the hose clamp / rubber seal that closes the vent hole on the side of the sizer. I could not make it tight enough to stop any more air pressure. I am thinking about tapping the vent hole and installing a small cap screw and copper washer.
Over all, I am very happy with the device and it is far cheaper than the factory option.