If you're talking about the spec-v, then it is 4x114.3. You can get those wheels from http://www.gruppe-s.com/Advan/advanrg.htm . They are pretty good people from what I understand, but I have never dealt with them. Nice choice of wheels. Quality, yet not insanely expensive.

I'm not to sure what offsets your car would need, but since it's fwd, I'd imagine you would need 17x7.5 w/ +45 offset? I'd ask other sentra owners though.