[GTJIM]

IMHO (that is for AnonyD!) The Opel GT auto trans is a standard GM TH180 gearbox as used in many Suzukis and other GM cars (including tens of thousands of Aussie Holdens). A full Master Rebuild Kit goes for around $200 to $300 and it should take a competent trans rebulider about 6 to 8 hours to fully rebuild one ... I guess $1,900 - $300 = $1,600 for rebuilding one - and guaranteeing it for 3 yrs is a pretty good hourly rate ....
Go find a good used GT auto trans and save yourself $1,800 .... IMHO

LOTS of rebuilders see "OPEL" and the dollar signs light up in their eyes - mainly because they want to cover themselves for working on something a bit unusual - once again IMHO