I need to replace the Serpentine drive belt on my 2005 Altima-S 2.5L motor,due to cracks all the way around the pulley side of the belt and the outer layer is scored around at the center of it. Is there just the main drive belt only or are there 2 belts that I have to change? This will be my first time to change an S-belt on my own car so I just want to be sure. Is there anything else that I should be doing to maintain the longetivity of the belt beside visually inspecting and tugging on it to check the tension, and what kind of special tool do I need to remove and install the belt?