You are right. The 08-10 air filter was different to the 11+ ones.
Are you running a dried one or oiled? I have an oiled one and can personally say that idle revving has a bit of a deeper tone as does the downshifting sound, ripping it through red line is the same though.
Current: 2013 Fire Orange E92 M w/orange stitching
Previous: 2011 Jet Black E92 M - 2006 325xi E90 NON-M - 2009 Volkswagen 2.0FSI MK5