this is quite a late reply but avo in cheltenham do everything. they have a 4wd dyno, they specialise in turbos, they can hi-flow your existing injectors (rather than forking out for aftermarket ones) etc. etc. they are better value than hpf who seem to prefer big-spenders in new cars.
i live in dandenong and look forward to checking out chequered tuning and autopuls after hearing about them on these forums, however cheltenham is not too much of a hike for the 4wd tuning and good general knowledge of avo turboworld. hpf didn't know how to tune my ems and then charged me for a few hours on their dyno despite not tuning the car. and since the guys at avo pulled my car apart and went over it with a fine-tooth comb, they are pretty familiar with the attesas now. tell them Richard sent you and maybe it will help with a good deal (?).
to be fair to hpf, they did do a very thorough job when it came to doing a roadworthy check, including wanting me to remove the oil catch can and sandblast my windscreen in the long list.
i'm also looking into new turbos... will keep you posted re my findings however i'm loving the sound of those chinese 2871's... rough price estimate?
and regarding dump pipe... seeing you're after the best, go for the CES racing dump pipe... fits with a minor mod: one inch of extra pipe welded on to clear the sump. expect to put a grand aside for that...