hi AH Sri Turb04, i can really only answer the 3rd question as i asked auz the question myself before he done my tune.
it doesnt matter which you do first,
if you were to get the tune first, then intake exhaust and piping it would be the same as doing intake first then exhaust and piping then tune.
you will get the same results no matter which order you do it in.
its best to seize the opportunity for the tune when auz comes down.
otherwise you could be paying 1000+ elsewhere (from what ive read in other topics)