We had a customer recently crack an aluminum plenum with BOV mounted on the plenum, but he is running nearly 15-20 psi. He is adding a second BOV on the plenum and having his original plenum re-welded and reinforced in some particularly weak places (around the perimeter in particular).1. How much boost are you running?
2. In your photo, there should be 4 nuts in the center of the lid. One side I can't see since it's blown off, but the other doesn't have any? Was this plenum modified?
3. Both of those plenum options are a waste of money. As Ferris said, you need your BOV at the plenum, close to the TB's. I've never blown one this way, even with plastic lids at 10psi.