I have Alloy USA axles in my car for years, and they come with a 10 year warranty. They are 28 spline axles that I use with my stock diff. I don't know what the hype is about upgrading to 31 spline. It's been like a chain reaction that has never stopped haha. If my stock differential breaks, all the aftermarket companies make a 28 spline diff that I can replace it with.