This TST is the system I got last year before a 1,500 mile trip, it saved me from a seriously over-pressure/over-heated tires (the difference being between leaving in low 40's temps and ending-up driving in 90+ degrees on black asphalt interstate). And I've had slow leaks before getting the system...it would have alerted me before damaging a tire sidewall. Seriously worth it IMO!
If you go with these sensors (I'd recommend against their "flow-thru sensors), you'll need metal or high-pressure reinforced brass valve stems.