1. Yes it will plug straight into where the original ECU is
2. Any good tuner can tune via laptop I believe, www.nengun.com also provides the screen for digital settings, im not sure if it can tune via the display unit though.
3. I believe its got the usual goodies on there, + Z32 AFM, 550cc injectors and hks 3037? (i THINK!)
mmmm gtst
PS. If your that keen please PM and Ill give you the owners phone number of the ecu and he will tell you all you need to know! Im pretty sure Ive got it covered though!