The 450 offered in SC boats is actually the 460 with a smaller diameter exhaust. To my understanding it is more than just different "tuning" when comparing to the 400. If I remember correctly it has different heads, cams and a couple other parts. I will look for the info I had on it as I did a fair amount of research before I opted for the 450. I know in 2019 when we ordered our Makai one of the big draws for the 450 was that it was already mated with the 1.76 Transmission. I haven't ridden in a 2020 with the 400 and the 1.76 yet so I can't compare but I know that was a solid move by SC.