it says when picking the difficulties that by playing on hardcore and insane u get a bonus and major bonus of xp earned respectfully. although this is harder it will lower the number of play-throughs quite a bit i think.
GT: MASS D0MINATI0N 101 completed games 79 Retail - 22 Arcade
Mass Effect 3 - Liara & Garrus conversation:
Liara : Did you really take out three Blue Suns mercs with one bullet?
Garrus:Nah of course not... The third guy had a heart attack. Not fair to count him.