[Mark N.]

It occurs to me after lots of testing, using the system and forum chat that the TST-507 is great at a couple of things and lousy at a couple more. Let me explain:

First, as a tire pressure monitoring system, in the purest sense, my own system is very inaccurate. It measures low, across all 8 sensors I own. Quite low actually. If I tried to set cold tire pressures to the readings I get from it, I would be over-pressuring my tires significantly. I took care to make sure it was not an error in my test gauge. I used 3 separate gauges and had 2 different tire stores confirm my gauges are accurate. So, when I say my system is reading 6 lbs. low, I am 100% sure that is a fact.
In a reply from the company, they suggested tightening the sensors another revolution or so on the valve stems. Sorry, but when I install them, there is not another revolution of tightness left! I snug them up tight and that's it. No more to go.

Next, the plug connector that powers the unit leaves a lot to be desired! When inserted into the base, it is not seated anywhere near flush. A significant part of the plug is left exposed and renders it vulnerable to bending and damage. It really, really, needs to be re-designed to plug in tight and flush. Poor engineering. The other thing about that bad plug is, at least on my unit, if you even touch the plug or disturb it, the unit looses power momentarily causing it to beep, then reboot, taking several minutes to regain pressures from all tires. This is the second plug they have sent me, with the same problems inherent.

Now, the positives: As a pressure CHANGE monitor, it excels! This, is after all, why I bought it. To be alerted to dropping tire pressures. It does this very rapidly and effectively. I want to know if a tire develops a leak. I know it works well in that regard.
Next, as a temperature monitor, It seems to work well too. If a bearing starts to over-heat, or a tire starts to suffer a tread separation, then overheating can result, and I might be alerted to the problem BEFORE a catastrophic failure happens.

Be aware, you will need to play with your high-pressure alarms to keep them from sounding needlessly. I really don't get the high-pressure limit alarms anyway. If you are accurately setting a tire pressure cold, you cannot ever get to a dangerous pressure level.

Bottom line is, don't rely on this system to accurately show tire pressures. At least in my case, it is very inaccurate. You just absolutely need to use an accurate and trusted tire gauge to set your tire pressures.
However, as a pressure CHANGE monitor, it works nicely. As a temperature monitor, it also seems to work nicely.

The power plug is a potential problem, and prone to bending/damage because of it not sitting flush to the unit when plugged in.

Would I buy the same system again? Hmmm....Good question. I would at least read the reviews of some competitors before making the decision.

These are my opinions, based on my experiences with the unit I purchased.