The actual number does not matter that much and depending on what brand of tool you use, that number can change. Harbor Freight sells a kit that most people buy and that I also own. What is important is the variance between the numbers. Toyota states that any variance more than 15 PSI less than the highest compression is out of spec. This is also based on:
- A fully charge battery reading 12.8V when off
- The engine being spun at 250 RPM by the starter
- The maximum compression being no higher than 174 PSI
- The maximum pressure reading being above 145
Since that list is really hard to duplicate, most of us stick to the 15PSI or 10% difference between cylinders. So if you do a check and you get say, 150-160 PSI across all 6 you're doing great. Don't get thrown off by guys saying they have 200 PSI or those that say they have 140 PSI, as there's too many variables between the tool being used and the conditions listed above.