Dan, don't worry mate, nearly all the DRB's in Aus fitted with T5's use US sourced units. And I expect a lot have cable clutches.
Been a long time since we last sighted the bottom of our old Torana based DRB, but we ran a US T5 and ran the clutch cable forward from fork and looped it over to the drivers side where the sump humps up. From memory we just used standard Ford clutch cable. From memory it was a very quick and easy job. And result was a fantastic feeling clutch, not too heavy etc.
Can't remember specifically about the exhaust, but we had shorty headers made, so no problems with those.
OK, see if I can dig up a photo & scan it in. Voila, here it is:
