initial D is REAL!

I am looking to buy a tial BOV, and I was wondering which spring pressure to get. I know it's bet ot put it on hte car and then adjust and figure if you need more or less, but i'm wondering if someone here with experience can recommend the right spring.
My car is a s4 t2 with a bnr stage 2 boosting a tad less than 1 bar. Thanks!