Are you interested in numbers or driveable and safe performance?
If the former then crank the boost up etc, etc and get your numbers.
Personally I like to be confident that the car is driveable for everyday use and that it won't go bang on the track.
Just for the record an '06 STi with full MMS TBE and Tomei unequal length headers got 197 KW and 410 NM on the same dyno.
It all tails off after 6000 rpm...the set shift light point should be about 5800 to make maximum use of the torque.