I was reading about Subaru's new 2.0L boxer for the Forester, with the twin-scroll turbo. Just wondering if this could be shoe-horned into the FT86 and mated with the stock transmission. Seems like a nice fit. Maybe slip in a differential from the IS-F and you might have something there.
http://dp.subaru.com/dp10-3-twin-scroll-turbo.aspx