I received the new updated fuel tank for my 818 and the design and instructions seem like an afterthought. Here are some issues I had with the process so far.

They provided no bolts to hold in the OEM pump and level sensor.

The subaru uses 2 level sensors in the tank and the area they are to be reused makes the level sensors sit on top of eachother and not work. I had to modify the mounting holes and flip the sensor around to point in a different direction in the tank.

There are no mounting tabs on the new fuel tank. So there is no way to secure it to the frame. The new firewall they provided holds down parts of the tank, but if the car were to release enough load on the suspension I feel like the tank would be able to move.

I am making some straps to tie down the tank as well as some rubber padding to prevent rattles.

Anyone with the new tank experience anything like this yet? I haven't seen many posts of people who have installed it yet. I will update as I complete the tank installation with any tips.