while this is going to sound harsh, I daresay the mismatched/carbon fiber bonnet look contributes a lot to that - your car stands out and they will pull you over. Once they realise that you're a young man too, then you'll be fitting the classic yob stereotype (again no offence because I know you're not a yob, there is a demographic however...)
I've been pulled over 3 times in 3 years, each time its just a quick breatho and licence/rego check. I can honestly say I've never had an issue with any of the police who've pulled me over, who've been very professional and courteous - one even asked me if I get much negative attention from SAPOL and the answer was no... its not to say that there arent cops who have a bad day, or jump to conclusions, however I've never had an issue. Maybe its cos my car is white, or that I'm older and fatter than you (which police love cause it means they know they wont have to jump fences to catch me) but there it is... if I'm unfortunate to get someone with attitude, well, I know what steps I need to take to ensure their job is carried out to the proper standards.
the irony is that I'm probably pulling the same amount of power as you and my car is older...
and damo, I don't think tangles was implying that you're stupid, however given that the NS crowd are often a bunch of tossers, if you go on an NS cruise you're likely to get tarred with the same brush. Its sad that it happens as Mark has everyone's best interests at heart and its simply a bunch of dickheads that are spoiling it for the sensible ones. And +1 to the idea of taking down registration... I myself will be buying one of these http://www.vsport.com.au/ecommerce/index.php?productID=362 and mounting it in my car to record my 'pleasant country drive'.... if any dickhead starts doing doughnuts or driving like a tool, I'd be quite happy to provide SAPOL with the video evidence.
-D