First the Pressure Pro system does not operate like most of the others.
The pressure Pro has a loss of signal alarm in about 15 minutes. It is a flashing red led on the tire that has lost communication. The flash is continuous and not a single beep that the TST has.
I prefer the external antenna.
External antennaI tried the repeater when I first got my Pressure Pro system.
Two problems. First where to mount the repeater which requires a source of 12 volt power. Second it was not water proof thus has to be in a weather protected area.
I tow a small untility trailer behind my 5th wheel. When I checked signal strength with the Pressure Pro the sensors on the utility trailer were still marginal with the repeater which was installed under the bed in the front of the 5th wheel.
With the external antenna located on the receiver hitch of the truck all signals were strong and the antenna is weather proof and requires no external power.

I use this antenna with my TST system and it works good.