The connectors on both ECUs are completely different. You can reuse the existing wiring harness by repinning it to the new connector. A better alternative, in my opinion, is to sell the existing kit with the wiring and injectors, and buy a new wiring tail with the new ECU.
The usual upgrade path is as follows:
- Red VAG coil-on plugs
- 600–800 cc injectors
- Performance fuel pump.
- Fuel pressure regulator with vacuum connector
A new turbocharger and 60–2 trigger are highly advisable, but you can stick with the old parts for now.
