What Volvo is it from? If you're referring to a Garrett, I wouldn't bother using that over a TD04. I take it it's comparable to the GT17 used on the Linear, so it would be a better idea to upgrade to a TD04HL-15T or larger.
If you are indeed talking about the Mitsubishi -15T turbo the CHRA might fit but I doubt that the exhaust and compressor housing are the same.
you could check the banjo bolts to see if they are the same with the Saab turbo as a first check.
But if you're looking for a complete turbo swap with the lines I highly doubt it since the location of the ports for oil and coolant are nowhere near common between the Volvo I5 engine and the Saab I4.