I bought an axle from Autopart International for $88. Not sure how much I wanna trust an $88 axle but we'll see. Are there any differences between an RS6 axle and say an A6 4.2 or S6 or allroad axle? It's fitted in my car and so far works fine, though I haven't tried any WOT driving yet... I saved my old axle to rebuild just in case.