I sent you a personal reply MotoRaider
The problem is I didn't just retro the gauge alone onto my pre-'02, but the whole wiring harness & ECM
Most of all the warning lights and input signals come from the ECM but it would still be possible to wire them up off your old harness. For a sender you use the electronic sender from a Sprint - exact same fitment as the 97-01 S3 wheel.
The biggest obstacle is getting a harness adapter to interface with the intrument cluster - that is not available freely, is part of the whole harness. I don't know how you could get that without buying a whole used harness from an S3, Sprint RS or Daytona.
The problem is I didn't just retro the gauge alone onto my pre-'02, but the whole wiring harness & ECM
Most of all the warning lights and input signals come from the ECM but it would still be possible to wire them up off your old harness. For a sender you use the electronic sender from a Sprint - exact same fitment as the 97-01 S3 wheel.
The biggest obstacle is getting a harness adapter to interface with the intrument cluster - that is not available freely, is part of the whole harness. I don't know how you could get that without buying a whole used harness from an S3, Sprint RS or Daytona.