I'm not so sure about G-tech accuracy. Folks I know who've tried to be scientific in comparing G-tech results to track and dyno results consistently showed that G-tech results are optimistic. But a G-tech is a heck of a lot cheaper and easier than a full-on tuning regimen. At boost level A the G-tech says 10 seconds, at boost level B the G-tech says 9 seconds. The difference tells me more than the absolute numbers.

The 10 second SD or 9 second SDL or 28 mpg 500SEL claims are difficult for me to believe. I'm not saying you're wrong, I'm saying I put stock in brainful of data that suggests these claims are beyond what I consider to be an acceptable range of variance. Are there anomalies out there? No doubt. What I have to decide is whether the anomaly is your car's state of tune or your methods. I don't have enough information to make a call.

Sixto