Hi Laszlo
OK the orginal number you have listed, 90351650 is listed in the UK for a Vauxhall Carlton/Opel Omega A with a C20NE engine fitted. It has an ID Code of GG and was fitted from Chassis Number L1019855
The next number you list, 90233741 isn't a good number on EPC, it may have been superseeded
The last number, 90351648 is listed for a Vauxhall/Opel Calibra fitted with a C20NE engine.It has an ID Code od GE and is fitted to vehicles upto Chassis Number M1073383
Also listed for the Vauxhall Cavalier/Opel Vectra A, again fitted with a C20NE engine with an ID code of GE and fitted from Chassis Numbers LV100001, L1000001, L5000001 onwards and is not used with engine immoblizser
So from that i woulds say that the first number is incorrect for the vehicle if you have a Cavalier/VectraA/Calibra and the one you require is the last number 90351648.
If you want to send me the vehicle chassis number i can tell you what should have been fitted from the factory as the Opel version might be different from the Vauxhall version
Cheers
Andy