Any Turbo rated oil is fine. Just be sure to regularly replace it, otherwise you have to cleanout the exhaust oil cover, to remove the scale of carbon-oil deposits, which build up and stop the turbo from turning freely.

The turbo is well under-rated (But still lots of fun for 6 months). As for the blow-off valve ..there isn't one. Use a recirculating one from another car eg. SR20DET or Lancer GSR/EVO.

Injectors max out at about 150kW, so you'll need 440cc or 550cc ones, if your turbo & internals can make the extra power. You'll need to get an aftermarket ECU, or get the original remapped to suit. The smaller the injectors, the better the idle will be. And for city cars, this is an important consideration. Stalling the engine at the traffic lights is "very uncool".

Chris