You could use cat certs to fix the plug also. They are like timecerts, but have 4 locking tags that keep the insert from coming out. The biggest downfall to them is the hole size you need drill to fit the insert.
I live in wy. If the Cylinder doesn't have scoring I could honestly see the dealer trying to throw a piston or piston/rod assembly in there and see if it seals up. I would hope if the dealer sees scoring they would just replace it, because they would be money ahead.
I'd ask about scored Cylinder walls and what are they planning to do about honing the cylinders walls so the rings break in correctly assuming there is no scoring.
Supras have all gen 2 b58 in them. Gen1 is in older bmws around 2017. I can't remember the years exactly, but they have a less flowing hpfp and different fuel injectors.
The 2 port and 6 port are just different model numbers. Kern 416 on you tube goes over it he is also on this forum.