you have 2 options.

The 48 off a cossie will fit ur turbo, but then the exhaust won't fit. It is however a much better housing, due to where the turbine and wastegate are located. You would have to have a custom down pipe made, or i can get u an adaptor that allows the std exhasut to bolt straight on.

The other choise is saab/integrale hosuing, which is the same as an RST one, just a 48