i would like to know where this sensor is located and how easy is it to install

well on my ser 1 its right above the oil filter. i believe ur 00+ is the same.

but a year and trim level added to your sig in ur profile, will save any readers to ur thread time of asking, and get you a faster answer.

Just above the oil filter to the rear of the car. Replacing it is pretty easy takes all of maybe 15 minutes.

and you dont necessarily NEED, but they make a special socket for those, well worth the 5 bucks