picking up the E8 260 next weekend hopefuly, allready got a hks induction kit and a 3" full system with decats, which is the best ecu to go for, it has been suggested to me by a ralliart specialist that the autronics is the best?
The question you need to ask yourself is 'What do i want from the car in the long term'
If you want a good, mild power increase and nothing else then something like a Ralliart ECU or an EcuTek will probably suit you better.
If you intend going further (~350+) with extras like switchable anti lag and launch control then a fully mappable ECU is probably the way forward, Autronics, MoTec etc. Rather than pick the ECU, you are much better picking a tuner and using the system he is more comfortable with.