Lately I was at my Toyota dealers showroom and I could show them oil leaking from a brand new GT86. The reactions to that was like
no way, it has to be like this... ahh it's just dirt... finally
...
My fix:
I've cleaned and degreased the stiuuupid leaking plate and put some heat resistant silicone to it. I also applied new silicone to the (degeased!) counterparts (engine block) and screwd the plate on again (16Nm, 11.8 ft.lbf).
Picture after disassembly:
EDIT: After one week of daily driving I can report that my fix holds together. No leak, no smell.
I used a good amount of something like this to replace the old silicone sealing (Originally Subaru/Toyota uses the grey Three Bond 1217 silicone on the leaky plate):
Heatresistant silicone (red): Subaru/Toyota uses something similar for the gearbox of the 86: Three Bond 1281 (don't use with copper parts!):
For the leaky-plate the red stuff works perfect in my case.
So I'd recommend Three Bond 1281 or similar if you fix it yourself.