RE: RS6
there is a reason they are now in your price range.
if you buy an rs6 you will regret every minute of it. nothing but a maintainance nightmare. do some research on the v8 bi-turbo. i had no problem with my b6 s4 and if i had the funds to buy another just to DD i totally would.
but again given the choices you provided…
z4m > s4 > a6 > mustang
I have spent a few days trying to research the car and am not coming up with a lot of reasons not to buy one. I know B5 S4’s have a really bad rep but the only 2 I have exp with were not bad at all. i’m all ears if you can point me in the right direction.