I found a local company that can do an
ECU tune. The bloke appears to have a lot of experience, so will be interesting to see how this goes. He recommended tuning for 98 RON fuel, noting the knock sensors can limit power in lower RON fuels. I will upgrade the exhaust first, the get the tune done. He was confident that tuning the NA engine will improve throttle response and driveability reasonably well, with a likely 15% power increase, but much better torque curve.