I just bought the TST 507 with flow through valves. I tested it last weekend with good results. There are several good TPMS on the market. I liked the idea of the flow-through valves where you don't have to remove the monitors to add air. However, you'll need to have metal valve stems to use that model. On the trip, it cycled through each tire showing pressure and temperature. Seemed to work well.
I could use some ideas from the group on the best way to install the signal repeater. It looks like it could get attached on or near the battery box. But, it would be nice to have a shutoff to prevent draining the battery. How did you install it?