the laval dealer had a car with the M exhaust not too long ago.
both sound great... akra is slightly quieter unless you are going for the full set up (with x pipe), otherwise the slip on version is quieter than M exhaust.
between the montreal m3 members i know, none have either exhaust youre looking for. gewow (LSB m3) had akra before but not anymore... as for M exhaust, you can hear it at the dealer. thats where i heard it before.
by the way, this post shouldnt be in the "for sale" section.
Current: 2013 F10 M5 & 2013 GLK350
997.1 GT3RS (gone)
2009 WRX STI (gone)
e92 M3 (gone)