If it helps I asked a well known tuner in adelaide about a custom tune for my Z20LET and was told a unichip piggyback ecu was the go, I'm not so sure about the specifics of features and the like but seemed to have some goodies like remapping throttle response with the fly by wire accelerator, launch control and mapping our cat errors. He showed me a dyno map of a Z20LER he had just done with really good gains, quoted $1850 to buy, install and tune