The NGKs were US$50. The TRD are US$100, and the magnecore are more. I've had the magnecore and the built quality was crap. It broke in 6 months. As said the stock units are very good, so I didn't see the need to invest in the higher price leads. In Jamaica the stock wires, new, cost twice the price of the NGKs which is why I bought them. Saw no need to pay twice as much for a stock item when I could have uprated ones for less.