I commend you OZ SPORT for pushing the independent research requirement. I am not sure if you are familiar with ECU reprogramming or if you have done a few yourself or not. The thing is, I have and I have worked in the industry for too many years and have seen the best and the worst of this issue.

Please spend a few hours looking at what these people are doing - openecu.org • Index page

Then ask yourself why all these people are looking to buy another factory ECU - openecu.org • View forum - Private Classifieds

In that forum you may also come across a few people who have a locked or as the Yanks say 'bricked' their ECU after an attempted re-flash like this guy -
openecu.org • View topic - EDC16 failed while writting. ECU locked?

All I am saying is that there are risks involved with re-flashing.

I still maintain that the best result will be a re-flash by a very experienced tuner and not from someone who knows how to fiddle with a few tables. This is because the manufacturer has the resources to allow thousands of hours of engine cell, controlled lab work and road data mapping the engine fully to arrive at safe tune. A competent tuner should know just how much they can raise the level of the tune without sustaining engine damage, however to find the limit of any engine means determining where the ragged edge is and hopefully tuning to stay safely away from it!

In Perth there is another BMW enthusiast who knows of me. Apart from his E30M3s, he also has an E53 for his daily transport. Check it out here.
http://bm-autohaus.com.au/

I trust this information will be of assistance.
Cheers, Dan