While their springs are generally a good idea, they want to sell you their whole valve train as they say it matches, well I dont like their lifters. They make a big deal about spring wire lock rings failing and use stamped lock rings which they say are bulletproof. Well show me the data where spring lock rings fail. I have machined and installed the stamped lock rings they use. They are not bulletproof and they weigh more than spring wire ones. They make a big deal about stainless rocker arms galling. Theirs are extruded aluminum and I don’t use aluminum rockers on street engines cause they will eventually fail. From what I’ve been told they do sell killer cam grinds and their springs match their cams, but for other valve train components I feel there are better options out there and their hyperbole is all sales tactics.