Which one to buy?

[xsx450]

I am going to make a completely uneducated guess which is what helped me when purchasing mine.

Get the newest one with the lowest mileage you can afford. For me this was an 06 4.8is with 65k. Previous owner has 0 issues, I am at 75k and still 0 issues. Trannies (~$4K) and air bags (~$1k) are big "maybies" on these cars so if you wanted to be 100% safe and had your heart set on owning a e53 for a while. Either purchase one that has had these rebuilt at your current budget. OR if you budget is say 20k, find one for 15-16K and put the 4-5K in the bank and tell youself you bought the car for $20k with a rebuilt tranny pre paid, and new airbags pre paid. And if they never fail then you are in a much better situation that if they do and it is not budgeted.

I always believe that the latest model of a series and the last year is logically going to have the most updated parts in it. That doesn't mean things wont fail...