I run a Hero 2, I was going to get this mic soon for autocross season: Audio-Technica ATR-3350
http://www.amazon.com/Audio-Technica...o-Technica+mic
It seems to be the go-to mic for go-pros. It is indeed mono but works. I'm afraid to drill my case and I may just suck it up for a new one....once in awhile I do drive in the rain.