I've considered ECU upgrades for my 1.8 Duratec, no conclusions yet and not a really serious problem as I don't 'labour' it at such low revs in 5th and prefer to run at 2ooo revs in a lower gear eg. 30mph in 3rd. I've got a K&N filter which helped and 98 octane fuel certainly also helps to eliminate the pinking, as well as a sound thrashing now and then to keep it 'sweet'.
As I understand ECUs, they re-adjust to style of driving and the more I regularly open it up the better it runs...the Italian Tune Up! On investigations so far, I was told it could take several hundred miles to get the ECU to re-think what is required of it eg. 'get used to' higher octane fuel or driving it more energetically. I'd try dropping a notch and make the engine work a bit more, especially if it's used to cruising at low revs in high gears.....more fun too.
Cheers
