You will find different opinions and many reasons some belive you can use regular but why do it? Your motor will detune itself on lower octane gas when sensing engine knock. From what I have read, the 90 hp turbo .9L motor in the 453 is capable of output all the way up to 120 hp with the way it is built internally. There are a couple places selling performance upgrades that really make the .9L turbo engine shine. The bottom end versions indicate 15-20% increase in hp and torque. I have had one of those on my 453 for a couple of years and really like the noticeable difference it has made in performance!Thanks for your quick response! I hadn't found anything newer than several years ago on using a different grade of gas, so appreciate the input. And will do!!