Hey bro,
Check this thread...http://www.skylinesaustralia.com/forums/topic/354799-starting-to-think-about-compliance/
I was the OP, disregard the Plan-FAILURE, mods being nazi faggots.
FMIC and exhaust shouldn't be a prob. As the above thread details, the focus seems to be more on everything being bolted down and nothing rattles/moves. Probably something I will be doing with the FMIC will be just putting mesh in the front bar as I've heard some people have been knocked back for an exposed FMIC. Aftermarket exhaust is fine as long as its within the sound threshold. The more original it looks, the easier it will be to pass it seems.
You will definitely need front and rear bars as well as the glass but I'm sure you know that haha.
James