Depends on what you are after. I have had very good luck with strange to rebuild my struts. If you are doing something outside the norm, Pro Mod, X275 etc then I might look at some custom valving program, but given most struts have very little movement in them for us average racers I dont think you are going to find a ton of improvement over what they can do. I just had a set sent back to convert from single to dual adjustables.