Originally posted by ManTiS
In another thread, you said you had some 'other' ECU program. This most likely advances timing and adds fuel which will require the premium.
A stock/lightly modded D16 needs nothing more than regular. You must have the wrong manual for your car because I know the sohc does not need premium.
I had problems with regular gas before I modded anything on the drivetrain. Maybe it was the MTBE in the fuel that was hurting - I now live in an area that doesn't dictate adding MTBE for emissions purposes.