Greddy has released a kit for the GR86/BRZ that routes the coolant to a core before going back into the OEM regulator.
https://store.shopping.yahoo.co.jp/m...-12015700.html
I'd suppose at that price point, one would just opt for an air-to-oil cooler but what would be the advantages of this setup? At the top of my head is that coolant is cheaper than oil and with the reduced risk of spilling oil.