OK, my turn...
I have delt with and know most of these workshops and their owners...
They all know me also,
I have to say that SEQ is very lucky to have so many places to take a skyline these days.
I have to say that all the above mentioned workshops are all pretty good, however in saying that you will always find one bad experience for every good one. Every workshop gets equal amounts of praise and bagging. I have to say tho, all these guys mentioned are all pretty good in my eyes.
Matt Spry if generally known for being the best at it as thats all he does.
The rest are multi purpose workshops which may or may not be a better thing.
Choice is yours, all I can suggest is use someone with an actual pfc lap link and software (which all of the above have). Dont fall for a chump who will tune your car with the hand controler. (Assuming you have a pfc)
My 2 cents