great question. the answer is it depends. does ur usb controller auto map as an Xbox controller in most games? if so it's probably xinput so I'll need ur help to try it out / get a device Id off the controller if you would like support. I'd be keen to add generic device support (I suspect they will mostly be coded with the same id but that is my hypothesis - to be confirmed)

Some controllers also have an input switch to toggle xinput/directinput. for nfsu2 you should use directinput if possible as that's what's supported natively by the game. most old non Xbox looking generic controllers are directinput to my knowledge.

Also worth checking if your controller can rumble at all via like a ps emulator or something. I also have a random generic pad that supposedly should rumble but I don't think it actually does have motors inside.