M3 is the obvious answer for performance. However, if I had cash now I keep on falling back on the RS4. I was set on an RS4 for a long time just because I can't resist it but then I sat in the new M3 4 door and fell in love. I think I would be dumb to spend the same money on an RS4 when the M3 4 door is that much better..If I lived in the North though I know which one i'd choose.. hands down.