Adam at tune+ says injectors without hpfp is fine, Jason at dizzy says not fine. I’d do both or neither personally. S280 is about perfect for the stock fuel system. You will be shocked how much faster the car is with the turbo and no additional fuel. Can always add fuel system upgrades later.
As for other mods, I’d say send it. As someone else said a crossover might help but definitely don’t need anything else.