Having owned a 6 speed 2009 E90 M3 then a 2011 C63 and i am back in a DCT E92 M3. I can say the C63 is better for DD since its a bit more comfortable and the transmission is silky smooth compared to the DCT or 6 speed from BMW. You do sacrifice something with the C63 and that is fuel economy, if you dont mind that get the C63. I havent owned a IS-F but drove one, i hated the obnoxious beeps for shifting, i hated the brake and steering feel as well and the transmission almost always struggled to find the right gear while in D.
-If you want a drivers car get the E-90 M3 (Though i would not since you already own a E-92) Keep in mind suspension and gearboxes are rougher than in the C63.
-If you want power and comfort and dont mind sacrificing these things for fuel efficiency get the C63.
-If you are a hipster and think the C63 and M3 are too mainstream get the IS-F.
l 2011 E-92 ///M3 l 2014 F30 328d M-Sport l 2012 VW Golf Tdi l 1997 E-420 Sport l 2014 Touareg Tdi Armoured Level B5 l
Compensating a heavy car with horsepower is like giving an alcoholic cocaine to sober him up...