Welcome to the QLD SAu community
Depending on how far you are willing to travel but theres a few places. Theres Gavin Woods - Autotech (www.autech.net.au) down the coast at Labrador that many forum members use or there's Mercury Motorsport (www.mercurymotorsport.com.au) over at Wilston that are a sponsor of the SAu QLD club. I personally take my car to Gavin and have been for the past two years. Never had a problem. There are a few tuners around the place. Gavin Woods, Mercury Motorsport, Matty Spry, just to name a few.
A great way to meet some of us is to attend the regular thursday night meets which are posted in the events section or the Cruise out west which is coming up within in the next three weeks. Also, the next Massive Skyline Cruise will be held by the end of this year.