Crackle maps can damage cats over time because unburnt fuel ignites in the exhaust. If youre catless, its less of a concern. But it does put extra stress on the turbo.
Hub dynos (like Dynojet) typically read 10-15% higher than roller dynos (like Maha or Bosch). This is because roller dynos measure at the wheels and account for drivetrain losses, while hub dynos measure closer to the axle. When comparing dyno numbers, always ask what type of dyno was used. A "400hp" reading on a hub dyno might only be 350hp on a roller dyno.
Also important: ambient temperature and altitude affect dyno results. A car will make more power on a cold day at sea level than on a hot day at altitude. Good dynos apply a correction factor (SAE or DIN standard) but the correction isnt perfect. For the most accurate comparison, always dyno at the same facility under similar conditions.