Might be dependent on state (NSW here) but I've got a mate with an S14 with fibreglass overs front and rear, 5 stud 17/18 stagger, fixed back, 300kw SR20DET - essentially every mod under the sun. The car has previously been red-labelled and since then he's obviously gotten it fixed. When he got it back on the road he decided to get every mod he could engineered so as to never face that problem again. Unfortunately I can't remember what exactly he has engineered on the car.
It just so happened that about 6 months after he got the car back on the road, he got pulled over when grabbing me one day. Clocked at 15 over I think and on full pelt when the HWP officer saw him. He produced the engineer's cert when pulled over and he got let off with a yellow label for the exhaust as he blew some smoke when he got on boost - I couldn't believe it as we pulled away from the curb.
Now had that happened with an un-engineered car, I daresay he would have gotten red labelled again - maybe he passed the attitude check, I'm not sure but I definitely think it's a wise thing to do if you intend to drive your car to events or you enjoy driving your car every now and then on the weekend or something. I intend on getting both my cars engineered when the time comes.