It's been my experience with one pulley that you can go hit or miss. What I mean is that if your running a stereo system you may drain more power than what your underfed alternator can produce or if one day you leave your lights on over night you may have to get a new battery. Also if you idle alot the car will not charge the battery on idle. I went threw this in my 300m I got sick of it and got the crossfire. Now some of may have had good experiences and disagree and I would like to hear what you have to say as well. My suggestion would be to see if anyone make a full pulley kit (more than just the crank pulley).