I use a spreadsheet to sum the changes in knock sum.
The parameter knock sum is present in most Subarus but is not available in the STi.
Here's an old copy of it. You have to manually change the parameters and cells. I used it for my own car and a few others. I would be careful using it because you need to check the cells to make sure that they have the right parameters or equations in it.
viewtopic.php?f=32&t=6313I sold my car and haven't really tuned a Subaru in a year.
