You're going to have to piece together the parts for a high performance UZ engine and it won't be cheap. This engine didn't "take off" in popularity the way the 2JZ engine did in the 90's.
Here's a laundry list of places to look for parts:
1. SC kits: Bullet in Australia
2. Cams: Kelford in New Zealand
3. Pistons: Ross, Wiseco, CP (all US based)
4. Rods: Argo in Australia
5. Valves & hardware: Manley in US
6. Injectors: Most Denso top feed injectors will fit the rails - you may have to change the connector housings to fit
There are no turbo kits that I'm aware of being sold by reputable people. The only kit that was available at one time was being sold by a huckster who has since been banned from nearly every import car forum out there. I'm not aware of anyone who bought/installed & ran his kit successfully.