You need to research the power draw of each component you are going to be running off the M2 to be sure that they are not going to need more than 160W at any given point in time. Keep in mind that you can never have too much power from your power supply in that 160W is the maximum wattage that the M2 can deliver at any point in time, if you need only 100W than you will have the same electrical draw with the M2 as you would with the M4.
The DVD drive is what really makes it tough. When it is not running the draw on your M2 will be significantly lower, however, when it is on. You just want to make sure that you can run everything all at once just incase it happens.
If I were to guess I would think that would be enough, but you should do the reasearch to be sure.