Im not sure what models have the omega, but I have had a regular cz75b satin nickel that was made in 2004, and its trigger was day and night compared to my 2011 model cz75sp-01 shadow. Im not sure if the shadow has a omega trigger, but it is a much better trigger than my older cz75b. I also spent a few extra bucks, and did a trigger job, which makes things lighter even still. Even if you get a non omega trigger, you can make it really nice & light by just changing a couple springs for cheap.
I think that the Omega CZ75 is not interchangeable like the rest of the lineup of CZ75s...i could be very wrong.