Originally Posted by Grendalf
This is happens to a lot of Subaru owners a few years ago. BOV do actually mess up the A/F ratio during shifts, you need a tune to compensate correctly and I am not sure if JB3 or PROcede can do that.
Regarding the choice of a BOV or not, I would get a new charge pipe with upgraded DVs which seems the best choice for our car.
Subaru owners were having troubles because their car are maf based. You do not need a tune to help run a bov on this car.