i'm wondering any of you guys know if i changed some aftermarket seats, will the the rest of the airbags (front)?? do i have to re program the ECU?

also will i still have warranty if i swap a sparco steering wheel instead of using hte stock one?

Stock airbags will work fine. Just don't sit too close to them if you want to keep your face in one piece. Resetting the ECU won't affect the airbags.

As for the steering wheel, I dunno why you'd replace the stock Momo but the dealership should be fine with it unless it's a problem involving the steering system itself (eg column, wheel, etc.)