Chiptorque here in QLD can do the full ECU flash for 3 MPS Gen 1 and 6MPS.
Mazda 3 has a boost limiter and torque limiter in 1,2,3 and 4th. Although 4th is like 95%.
Mazda 6 is a little different, they don't need the torque limiters in the lower gears due to AWD, but, they still have the throttle closing above 5200rpm ish.
Most places that flash tune the MPS, can remove the limiters.
The issue with the turbo, it produces heat after 18psi, stick to 17psi to be safe. It is also out of puff by around 5200rpm.
Make sure you get someone that can tune an MPS properly before you go getting it done. We don't want to hear about another MPS Zoom Zoom Boom story.
That's my $4500 worth.