Nuggets about block 5

Mane engines stepped up to 190,000lbs thrust with higher ISP.
Merlin vac increased to 220,000lbs.
The merlin vac is still throttled down to 210,000lbs to study vibration.
The octaweb is stronger aluminum 7000 instead of aluminum 2000.
The rocket base is now titanium with water cooling.
The black sections are a proprietary material, probably derived from shuttle tiles, but without the porous sections which absorbed water.
The avionics & IMU were redone.
Current 2nd stage recovery efforts are only to determine the mass impact of recovering it without impacting BFR development.
Falcon 9 launches would cost under $6 million if they could reuse the 2nd stage.
He wants to launch the same booster twice in 24 hours, in a demo mission next year.
The new COPVs are the most advanced & tested ever made.