for example with stock K03s, they can't sustain over 1 bar of boost all the way to redline. With the MBC set at 17psi, basically the wastegate completely shuts as you approach redline, and boost will taper down, as the turbos are pushing out the max CFM they can but it isn't enough to sustain the desired boost pressure at those RPMs. Makes a good case to run the MBC in parallel with the N75 in this case. With K04s at 17psi this isn't an issue though - all depends on where you set your MBC and what your turbos can do.

2000 6-spd