Remember also that CFM is just a number, measured in entirely different circumstances by different companies. Picking fans exclusively based on this is probably not the way to go.
As for damage, I've never heard of a fan damaging any component. Any decent fans come with rubber washers etc so they shouldn't cause much vibration at all.
Also, in an ITX system, you are always going to be pretty limited as to how much cooling makes sense. You still have a CPU and graphics card, same as any other system, but generally less scope for overclocking etc. Adding fans for the sake of it might make absolutely no difference to your system temps.