Wth... i installed my audio for my old car about 2-3 years ago at same store (Osborne Park), did it beautifully (cosmetically and quality). Was using 1 amplifier, 1 sub woofer, 1 set of 6.5" and 1" tweeter. And also was tuned properly with small mic that comes from Pioneer 7000 series for audio balance. All parts were from Ebay, including cables, battery terminal thingy, etc. And cost only like $85... coz i was working next door to them.

Can't believe they did dodgy thing on you. Who's the person name that did your car?

Cheers
Gerry