My brother ran by the same theory on his 89 Celica years ago. 7 engines and 5 gearboxes later he learned his lesson.Think about how fast you can sprint. Now try and imagine doing that constantly, no more walking, no more jogging, just sprinting. You are not going to be too well by the end of it. i agree with you mate its just logic and on my sportivo it says use premium only so thats what i do and ive been in cars that were running on premium and then reg ulp and you really notice it similar to having air con on in a car with sh itty torque like sportivo and fto etc