From my experience, the key to not getting pulled over and defected is quite simple and mainly to do appearance:
- Don't have a loud exhaust... (loud N/A skylines sound like arse/VL Commodore anyway)
- Always have matching rims on your car, no skid wheels...
- Dont drive around with unpainted bodykits/ different colour panels...
- Dont drive like a dickhead
Basically, the less attention you bring to yourself the better. Ive been driving cars for the last 8 years following this principle, and it has never got me defected even tho all of my cars have been defectable. If you do get pulled up, be as nice as possible. If you pass the police 'attitude' test, depending on the officer, they will be a lot more lenient towards you.