It's not 29 PSI boost, it's 29 PSI absolute pressure (from complete vacuum) minus 14.3 to 14.5 atmospheric PSI = 14.5 to 14.7 PSI maximum boost. That's the reading on my Scan Gauge (has 4 user definable digital gauges that can display any 4 datastream lines from the PCM, and a crappy code reader that doesn't always work... but I didn't buy it to replace the Tech-2 or MODIS
), as far as I know the measurement units can't be changed, but I'm getting used to subtracting 14 to get the boost. It would be nice to have a vacuum/PSI gauge, but for now absolute pressure will work.