225/45 Vs 245/40 For Autocross

I will be on the stock 18x8 rims and i'm purchasing Dunlop Direzza Z2 Star Specs. From what i've gathered, going from my current 225/45 to the 245/40 will result in a slight loss in responsiveness but more grip overall, and higher acceleration Gearing wise. These will be for autocross so grip is my main concern and i kinda wanted a fatter tire to cover more surface area. All last season i auto crossed a Goodyear all season tire, So as far as me noticing this decrease in responsive turn in, i doubt i will. I'm sure i will only see great improvements on every front (except tread life). But is it reasonable to go to the 245? Or should i stick to the 225. I like the idea of a fatter tire covering more ground for more all around grip.