Originally Posted by Levi
-RS5 is heavier,
-RS5 has does not have the good 6MT of the RS4, which is even better than the M3's 6MT
-RS5 does not look so distinguishing as the RS4
-RS4 is not so agressive as RS4, RS4 looks better than RS5 (subjective)
-RS4 has character, RS5 is bland
-Both have "the same" engine
-RS4 handles/feel better, more "connection" than RS5
-RS4 is "hard-core"
In one word, the RS4 has something that the RS5 has not, just like M3 E46 has something M3 E92 has not. But contrary to what M3 E92 offers over M3 E46, RS5 has nothing more to offer over RS4 except "bling-bling".
PS: I am also interested in your view point RS4 vs. RS5.
I agree that weight and manual box are two failings of the RS5. As for the areas of superiority.
Engine: more power and torque, wider torque band, wider power band, higher rev limit. Better economy and emissions.
Suspension: improved version of DRC, offering better control.
Select drive: ability to change characteristics of each item of the car and program an individual preference for each.
Quattro system: an improved version offering a wider abilities to switch available power, even quicker reaction times, more efficient, the ability to link with sportsdiff and provide a full torque vectoring system front and rear. Greater levels of grip approaching 1g.
DSG: ultra quick shifting dual clutch with no noticeable lose in power during shifts, plus the ability to offer launch control for the first.
I could continue but why bother as you will wash all these advancements under the carpet.