I had my hiflow turbo done by MTQ in NSW @ Wetherill Park in Sydney. Turbo was really responsive and I was pretty surprised at the power I got out of it. From memory I payed about $1600 for the overhaul kit, braided oil line, and change of turbine wheels to larger steel ones. They basically swap out your turbo if you already have a stock one available.
I had a similar setup to the R33 in this topic, but I also had a walbro fuel pump, new coils and no injectors. I managed to get 240rwkw!! Not a bad upgrade for the R33, and man it was fun to drive. Too bad I had to sell the car.