Some New Anti Lag options (rally style anti lag). I personally love the ALS on the drift car just keeps that turbo spinning while you lift.
Rally style anti lag tuning and system set up explained.
This s13 has the
secondary air injection kit I found this particular set up doesn't need much keep the turbo boost happy. On ignition cut set up at the track or under heavier use you do start to get a good bit more noise and flame. I like the ignition cut option as it helps keep heat/stress off the exhaust valves vs retarding the timing under ALS conditions.
Of course you will need to have a proper engine management system for tuning the ALS. Both the throttle bypass and secondary air injections can normally be installed and set up in 1 days work.