Take it from someone who knows, not the noob above who said the wrong cost.
It's 3 demerits and UP TO $1100. Car is only defected if it's actually defective. Also it is cops discretion whether they let you drive home or make you call a mate with full license to come pick up your car. Also you get a big black mark against your license plates so they'll ALWAYS check you whenever they see those plates. They now have scanners which auto-scan plates around them, and it'll flash up on their computer 'TURBO ON P PLATES xx/xx/2010' so they'll pick on you heaps once you been caught once.
Also remember they will go over your car.
BUT. Depending where you live it can be easy to get away with.
I drove a nissan 180sx for 6 months, sr20det pushing 180RWKW in a 1100kg car. dyno'd with 430nm torque...yes puts a lot of n/a 6's to shame, not bad for a mildly modded 2.0L 4cyl.. Did 0-100 in 5 flat. Had a loud blow off valve and 3" straight through exhaust. BUT I live in a fairly rich area with very low crime rate and not many cops around. I drove without P plates. Which means less chance of being pulled over, but if you do get pulled over, it's 5 demerits straight up (suspended 3 months) + ~$1350 fine. In 6 months I got pulled up 3 times
1. drug bus, couldn't avoid. shat my pants thinking as soon as they ask for license and see 'probationary' they'll ask where my p plates are. Then they'll probably notice it's turbo. Then they'll find the unenclosed pod, the 2 intake mods(only allowed 1), etc etc. Got some young chick. Breatho'd me, didn't ask for license, sent me on my way

2. forgot to turn my headlights on after training. flashed 'mate do your lights work' 'oh yeah sorry' turned em on and was sent on my way
3. drug bus again, again didn't ask to check license...dunno why cos I don't look particularly old...
I'd still be driving that 180sx now, except my god damn mother borrowed it, and never having driven a turbo car before, in the wet, came on boost coming out of a corner and slid into a pole when the unexpected power span the back wheels

Write off. Luckily it was over insured by like $4k and because of mum's tiny excess I made a profit

The only drawback is, every time I went out driving I thought 'hmm wonder if i'll get caught today' and whenever you see a cop your heart skips a beat. Also whenever I drove to the city or dodgy areas (springvale, dandy etc) I had to beg parents to borrow their cars cos the chance of getting pulled up there is too high.
Anyway I had my fun with turbos, now have a mildly modded fairmont i6 (5spd, extractors, cat, zorst, thermos, enclosed pod+CAI, stereo etc), have about 14 months left on my P plates and not a single offense to my name

Looking to go v8 after Ps...although I'll always have a soft spot for 180sx's, never have I driven such an awesome handling car which just begged to drift...
edit: Also yeah the cops scanners give the model of your car and the engine. I'm guessing most cops didn't know 'NISSAN 180SX COUPE 1992' or 'SR20DET'. But I'm guessing most WILL know 'FORD XR6 TURBO' LOL
edit2: It's less fun to drive when you're not meant to. Because every time you feel like thrashing it off the lights you have to look EVERYWHERE for cops. You're always looking out for cops. Now in my 5spd fairmont I have much more fun, bought it for $600, spent $3500 on getting it RWC with all the mods, and it is a fun as car to thrash around, should entertain me enough for the next 14 months anyway, and I'm not scared to drive hard everywhere because if I get pulled over, it's legal..
