Hello
With a good tune (not STILLEN) and your exhaust system
do you come about to 460 - 500
HP
Maybe something more ...
The power at the wheel, I can only estimate
Power loss to the wheel, we estimate between 12 - 16%
(See the calculator in the link
It is impossible to calculate these values accurately, this information should be used as a rough guide only)
Wheel Horsepower to Crankshaft Horsepower Guestimator
Hope I could help you that way
Do not forget to install the additional oil cooler
Greetings
Ivo