We've updated our reliability stats for the M to include owner experiences through December 31, 2013.
Repair frequencies, in terms of repair trips per 100 cars per year:
2008 M: 33, low, small sample size
2007 M: 59, moderate, small sample size
2006 M: 48, low
We have two additional statistics, "Nada-odds" and "Lemon-odds", to indicate the percentage of cars with no repairs in the past year and those that required 3+ trips to the repair shop:
2006 M: 60, < 1
We'll have further updates in May and in August. The more owners participate, the more comprehensive and precise these will be.
To see the repairs behind these stats, and to sign up to help improve this information:
Infiniti M reliability ratings and comparisons