On my previous vehicle (that saw some track time), I tried the HKS intake. Good performance, though short lived. In my opinion a K&N type would be better for the offroad environment as they flow better than stock with up to 1/8" of dirt on them, and they are washable/reuseable. I just put a Pop charger on mine (same as two other Nissans previously) and am very happy with the price and performance. Saying that the temp sensor serves no purpose if left in the stock location is somewhat incorrect. It will still register the temperature in close proximity to the intake and it will still allow the ECU to make adjustments accordingly.
Charlie (still just an FNG)