Considering the legacies are 2ltr you would sure as s*** hope the RS4 was faster. Just like HSV (Horrible s***ty Vehicles) they arent acheiving much when it takes 4 extra cylinders and at least 3+ litres to beat something like a little Subaru. Good job it never rains in NZ since Ford and Holden have no traction under power,corners or pretty much anything other than dry straight drag conditions.
New price vs new price, what you would save buying a new legacy or STi over buying a new RS4 you could spend tens of thousands on mods on the Subaru and it would kane the RS4 all day.
Look at some of the 600+hp Subarus in the states
Also stock Sti has better time round Nurburgring than the stock Audi so it depends if you want a drag car or an all round performance car.