Very good Ratbag, I have made this a sticky.
I will also note, that why these are the laws it is our own personal choice to abide by them or not. I myself run an illegal setup and anyone else who does should not be judged so on this forum but it is all well and good for people to be aware of the rules.
With lifting Subaru's. Legally 2" or 50mm is all that is allowed whether it be spacer blocks, raised springs, tyres or any other form of lifting a car.
Tyre sizes in WA, you can legally go 25mm wider than the factory specifications. Nothing is mentioned about height for the WA Laws. I have personally looked this up. I myself run 225/70R15 while stock is 205/70R15. These are around 3" taller in diameter giving me 1.5" of lift. This is included in the total 50mm you can legally lift your car.