Your right about treating them with respect. Worst case, if they randomly pull over for no reason, just act like you don’t know anything about cars and that you did not know anything about the modifications “done prior to you buying the car”. Not sure if this would work. I think unless your are driving in an illegal manner and they see you, or your car looks is awfully loud or slammed, then you might be fine. Put it this way, I am not too afraid when driving my sv6 with some mild modifications on my red p plates.
If/ when you have to drive like a hoon p-plater driving a Commodore or Falcon, don’t do it in an obvious place with people nearby or cameras.
Anyway, like you see on ACA or TV, a lot of p platers who get pulled over tend to be driving erratically when pulled over, or have a slammed Mang machine (Usually VZ commodore or prior) with tire slap all over the guards.
The moment you argue, disrespect them, or give them lip is when they will go out of their way (AKA take their job to seriously) to defect your car as best as possible.
If they pull you over (randomly for not reason) remember, you don’t know anything at all about cars, and you bought the car like this. Just act dumb and not give them an attitude. I’ll say it again, “you don’t know anything about cars whatsoever” when they pull you over. “It was just a cheap car you found for sale on Facebook market place, and they guy you sold the car did not mention anything about modifications and said the car was well looked after.
As those after market headers get rusty, they may look more stock. My stock headers were quite rusty.
Hopefully this is obvious, but advice given here will not have a positive impact on insurance whatsoever as insurance companies will try their damnedest to not pay out should they worst happen. This applies to anyone driving a stock Toyota Camry or a 900hp HSV Clubsport.