All good fella's thanx for the help, it was a faulty amp from JB Hi Fi
Pioneer 600w 4 Channel, so were taking it back to JB Hi Fi Myaree, im a apprentice electrician so i understood wat you ment when checking for dead shorts and shit, i took it out this afternoon, after the stereo shop who installed it told us it was the amp, and put my amp the same type but a 2 year old model in and it pumps hard haha

i never thought i would ever come across a faulty amp after purchasing brand new, my old one is cranking in the car now and i had it in my old ford (my first car) for a year and a half, and i used to hammer that with the sub in my boot lol

Cheers Guys
Nathan