Let's see: Mike's got a Speedster(CMC?), that's aircooled.
Not even close to a Beck Spyder with a Subaru. That will require a heater core inside the "box". The man with the answer is Carey Hines, but I wouldn't wait on an answer here. He's too busy building cars.
I'd bet the answer is closer to what Lane ended up with in his new Suby mid-engine coupe than anything else. Especially because Carey built that too.