Hesitation/stuttering would make me think fuel pump.
Popping and backfiring sounds like spark breaking down. I would start checking ignition items, plugs, coils, coil harness etc.
Is it s1 or s2 25? s1 will have a seperate igniter like 20/26, that could also be stuffed.
Does it do it everytime without fail? or only when hot? or just randomly intermittent?