I have NST pulleys for about 3 months now. I havent had any issues with them,, so far quality and reliability is awesome. After the install, i noticed some positve changes.. car feels better at revving. It was my first time installing pulleys so i cleared a whole day and installed them There are 2 biggest challenges (as for me). Removing crank bolt and 3 alternator bolts. I had Craftsman 590lbs air gun and it didnt do anything at all. So... as many guys here recomended, i used breaker bar. I was really scared to do this but it worked as a charm. To remove 3 alternator bolts..all you need is a few tools and some patience. I am 100% satisfied with the product. If you arent too comfortable with the tools or not really mechanically skilled, i would recommend to find a friend to help you or take it to the shop. Its not like i am a mechanic or super good with a tools, but its just my suggestion. The good thing is, you dont have to worry about quality and built of these pulleys because its awesome. Plus, as you can see, NST representative is always here to help. Hope it helps a bit...