If AEBS knows it's for a daily driver, they're not going to fill the deck. Besides there are many OEM turbo setups that run closed deck, look at the 4G63.
I didn't know that AEBS offered an option. I thought they always used a closed deck design.
As far as the 4G63, it was a cast iron block up until 2004. I always took the stand point that it was designed to be turbocharged, the block is much stronger. Heat will warp an aluminum block much quicker.