To answer the question, YES ABSOLUTELY you'll need an A/F controller for 450's.
Think of it this way, stock is 360, 450's are about 25% bigger (quick math). So you'll be runnng 25% richer. The car will foul plugs almost immediately.
As far as I know, our ECU's can't really be reprogrammed (DSM's can). And at $325 for an S-AFC it's better just to go that route.
BTW you can pick up 450cc injectors (not flow matched) for around $70 for 6 of them. Then $10-15 each for cleaning, I think an extra $5 for flow-matching. So really $200-220 is a decent deal, considering you don't have to go thru the hassle and wait of getting them cleaned/matched.