I believe my M3 with a build date of 3/08 has the new spring in it. It doesn't have the increased pressure on the top half of the pedal travel like my 335i does. It's more of a linear feel.
2013 Mineral White e92 M3 DCT ZCP
2012 Bluefire S1kRR Race DTC ABS QS HG
2008 Sparkling Graphite e90 M3 6spd XXX