S4 vs S5 halfshafts? difference?
 

I bought reman halfshafts for my car from advanced auto parts, i got series5 because i was thinking the engine was series five, i wasnt thinking about the rearend because im stupid. i didnt think it would matter anyway... but they came today it they dont fit, the bolt pattern is off by like a quarter - half an inch. is there any difference between halfshafts or did i get n/a ones? the two i have look identical otherwise, same thickness and everything, just a slightly off bolt pattern. any help is apprecaited, thanks!