whats the best reset process to follow, the 90sec with key in MAR or the battery of the negative terminal?
To do a ECU reset the first thing you need to do is disconekt the battery( the negative terminal) for 1h, to clear the "adaptiv memory" from data.
Then you reconekt the battery, turn the key to MAR for 90 sec., then
to stop, leave the key in and wait for 90 sec., then start the engin
without touching the speeder (throttle) and let it run for at least 15 min, i usually let it run until the radiator fan starts, to set new idle speed values, turn off the engin and leave it for 10 min.
Then if you want set the ECU to some "sporty" values take the car
out and give it a full blast (rev it full on every gear and full throttle),
but be aware that this values gonna change as you drive along in time, for the ECU adapts to your drive stile.