personally I want to swap a renesis into the brz. id cheap out by getting a S2 Rx8 manual and swapping the transmission and engine together as a unit, then calculating BTU capacity and maybe upgrading the cooling system
then throwin on huge series oil coolers from the RX8 with new setrab coolers, and using the OE Rx8 wiring harness to run the engine. but its a lateral move for something that doesnt exactly dyno more hp ( it will be not alot) but for me it will change the driving characteristics of it
and in the ideal world with money not being an issue id make this
TRD Griffon