Simon,
You might find an N1 that is close to the spec you require already.
This R34 N1 Vspec II sold at JAA Tokyo recently and has a roll cage, Apexi intercooler and some other stuff.
Shin or DCD might tell you what it says.
JAA Tokyo SKYLINE
Lot No. Year Model Type Displacement Fuel
197 2001 - 2600cc
Chassis No. Odometer Colour Trans History Grade
BNR34-401788 5,000km white Manual 6 Speed 3A
Air Condition Options
No equipment Power Steering / Power Window / Aluminium Wheel
Start Price Status Sold Price
4,400,000YEN Sale agreement 4,760,000YEN