I believe its going to be hella hard to fit that tranny in a bug, the hawkeye(06-07 STi) trannys fit with minimal parts needed.
06-07 sti 6speed (obviously)
driveshaft from a automatic impreza
you can reuse your clutch and flywheel, but why not get new ones that are STI spec?
as far as I know thats it (and obviously a 6 speed shift knob)
looking into doing it for my bug one day....