In my opinion, the e90 m3 is the greatest sports sedan ever made, and with the way things are going with turbos and hybrid performance cars, possibly the greatest NA sports sedan ever. Obviously the e60 guys would argue this.
Anyway - since you already have an m3, I'd probably go with c63 with those choices.
2016 GT4 - incoming
2011 e90 m3, 1993 e36 325i, 1999 e46 328i, 2005 ap2 s2000, 2007 WRX STi, 2008 g37s coupe, 2009 Audi a4 2.0T Avant