I know how you feel. Have had bad dealings with a few - particularly iDyno on the Central Coast who has the same personality issues from laziness (in 7 months he charged $4500 to sit an engine on a crossmember), spiteful additude and unclear on information and advice. Usually the advice is to buy something through the tuner for them to fit...
I've had many good reports on DVS Jez in Somersby. He is a massive enthusiast and outstanding customer service. He particularly works with RB26s but his knowledge extends to Falcons/Commodores and other Nissan varieties including CA & SR. I haven't yet had my cars tuned by him yet but he is my first point of call. I have had a fair few friends who have had drift cars tuned by him and he goes to the extent of making small details like cold start work properly. Expect a one month wait though as he is always booked.
Tuners are definitely few and far between - and how much they charge is never equivalent to the quality of work.
Best tips I can offer for a good tuner is that they should have a good mechanical understanding. I've met one who doesn't have mechanical understanding, he can push great figures but can't fault find. A good tuner should also do leak tests on the vacuum system, compression tests on cylinders and so on BEFORE they consider trying to tune what could potentially be a dud setup. These are the small details that make a good tuner a good tuner.
Best of luck!
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910 S3 Bluebird - FJ20ET, E85, IRS, 5 Speed, 4.4 LSD
910 S3 TRX - RB25DET, Coilovers, S13 Front end, Power Steering
RA23 Celica - 18RG, Twin 40mm Webers, Coilovers, rolling on SSR mesh 15x7 0s.
1600s arent the only datsun