'This system is for 1989 to 1999 Nissan Performance vehicles, you must have a NISSAN ECU'
and when you mean 'does it plug straight into rb20 ecu' ....No, is doesnt.
It plugs in a 'Diagnostics port', which is usually located next the fuses or in the fuse box under the steering wheel.
also i know in r34's its next to your right knee when you sit in the driver's seat.