BOV vents the pressure in the intercooler pipework to atmosphere when the throttle closes.
If you don't run one, then that air will have to makes it way back to the turbo.
Some info suggests that this stalls the turbo. I don't think it's a major issues at all especially with low boost levels like this.
I wouldn't worry too much about the hondata right now. Just run a socketed P28 and find a tuner that uses Crome or similar software.