You can't say that 500whp will take it out of the efficiency range by itself. Maybe boost, ok.... If I need to run 27psi to hit 500whp then mabye, but according to this 27.5psi could be had in the midrange tapering to 19psi or so at redlline. What this translates to in HP yet I won't know till the turbos go on but it is DEFINATELY possible to peak OVER 21psi and still be on the island.
2011 335is DCT, JB4 MHD BEF, stage 2 LPFP, e50 50/50 meth, FBO, MT ET Streets when needed