There is a bigger body of expertise at the site exclusively dedicated to boosted cars.
You will find entire threads on various aspects of tuners such as JB, Cobb, Vishnu, AA, etc.
You might try that site. I can't post it but it has:
Our forum is a great general forum but this one caters to the boosted cars.
Expect to be overwhelmed with information and you might well find another poster that has described the same problem you have...