From what I have read/heard/understood it is very rare for a turbo to fail because of a lack of
BOV... Although it definitely does put more strain on the turbo, and if left for too long, could probably bend the fins.
IMO get one on there as soon as you can... I have an APS which plumbs back most of the time and vents when on full boost.. I have also had a GFB Hybrid.. I would recommend both of them.