autozone suspension parts are junk. moog is good. xrf is the best if you can find them. as far as using moog numbers, moog has been so widely use that it has beome a standardized part numbering system for many companies. trw are not the same. moog is owned by federated auto parts. trw are ok. the simple fact is no matter which brand you use, you can expect to change s series ball joints relatively frequently. i make alot of money in the garage i work at changing them. moog does stand behind their product. they are easy to find. last as long as youre gonna find. the only reasson id suggest xrf is that the guy who started taht company was basicly the head of moog parts. he thought he could build the smae or better quality parts at a better price. so in a sense, yer gettin the same quality or better at a lower price. and to be honest, i usually changed out moog ball joints on the s-series about every 20-30k miles. ive seen 30-40k out of the xrf.