Welcome to OA, good to see another G SRi, especially in black
As for turbo kits, there are a couple of bolt on kits, or you can make your own.
The best for straight fittment would be the Dbilas kit, to suit the astra. This is around 5000 euros
There are heaps of places (Hahn racecraft for example) that make kits in the US for the L61, which will suit the Z22SE with some modifications (Intercooler pipes) needed to fit the astra, but you would need to find your own fuel and ignition control, as the ECU's are different.
Start a thread on your beast, so we can check it out.