Can anyone recommend an auto-electrician in Brisbane to do a "Big 3" upgrade?

I could possibly DIY, but interested to know what the cost would be to have a professional do it.

Basically it involves upgrading to larger power cables, ideally 1/0 AWG:
- Battery negative to chassis/ground
- Engine to chassis/ground
- Alternator to battery positive

The factory cables look pretty lightweight and I'm planning an audio system upgrade.

Hopefully the Big 3 will also give the electrical system a boost and make the engine idle smoother etc.