So you want to fit an aftermarket head unit into your Omega, well what you need is a display driver.
This enables you to see the current CD MD or radio station on the display, and control with the steering wheel controls.
The company you need is Connects2 -
www.connects2.com, they have a good on line help system with real people on the end.
Lets talk Sony - well it is a good place to start - especially if you have Mini Disc.
There are two adaptors available. DOPS004 (replaces DOPS002) and DOSP005 (replaces DOPS003) the only difference is the lead.
The DOPS004 has three two row plugs, and the DOPS005 has two two row plugs and one three row plug. I have noted down the differences and will post them when I find them.
If you hace a facelift you want DOPS005 - the Fisher Price CD player has this connection. Earlier Omegas appear to use the 004 - both CD head unit and cassette head unit were.
If you are not sure remove the head unit and look at the socket in the back of it.
I am also investigating an Autoleads PC9 350 but so far it just gets in the way and is only used for its three row socket (yes I shoved the Connects2 adaptor cables in it to convert my DOPS004 to a 005).
Now fitting these parts can be a problem - there is very little room in the dash, you have two choices.
1) Cut and join as many aftermarket looms into one as possible.
2) Extend and shove behind glove box
Edited - this is the layout of the third socket
DOPS005 has 3 rows in the top block DOPS004 2 rows
XX-XX-XX
-XX-XX-
XA-BC-XX
vs
AXXXXXXX
BCXXXXXX
ABC are display driving cables