I have learned the hard and expensive way with the Omega

If you don't wont to go all the way when lowering your Omega, don't!
Mine is lowered 40mm, and when going for 30 or 40mm lowering, the firs thing to pay your attention to is the camber in the back. There is a camberkit on the marked, from Austalia.
It's for the Holden, but it has the same chassi as the Omega.
They reccomend a camber setting for 1.55 and the combined toe for 0.20 in the rear.
The next thing is the donuts, this is what's holding the rear suspension in place, but they will flex a lot when phussing the car in turns.
So change them with polys from the same company. BIG change in drivability!!!
Then the shock's and springs. I'l rather go for sports shocks and standard sports springs then standard shocks with lowering springs. It's essential that when you lower the Omega more then 20mm, that you go for shocks that are rated for that, like the bilstein B6 or B8 and the yellow KOni.
Anyway, this is the setup for my car, and there is no unewen tyrewear

Poly camberkit in the rear, poly donuts, Cobra 40mm lowering springs and Yellow Koni's, adjusted to one turn in the front and 0 in the rear.
Camber 1,26 in the front. Toe combined 0.10
Camber 1.56 in the back. toe combined 0.20
The car is neutral in corners, before the rear end is starting to drift out, and it's very stable in hig speeds. A benefit from this setup is that the car is hardly roling in the turns, and it feels like you removed 300kg from the car

And the comfort, well, it's better then a corsa or Astra

This is a setup for the driver, for the looker, just chop the springs
