Ive installed one while running stock boost.
I didnt notice anything bad. Ive tested it with my Apexi RSM + Gsensor, and it stills runs very similar times.
However i did notice it slightly change the sound of my blitz BOV.
The reason why i installed it was because i am a uni student, so most of my mods i do on my car have to come in stages due to money restrictions!!
Next few mods will be HD clutch, then onto boost controller/SAFC2 i think! Then off for tune! So the bigger FMIC will be used!
But to answer your questions, in my experience, I didnt notice any negative effects.