FYI - There is no such thing as too much. The system will demand what it wants and the p/s unit will supply it up to its limits. Nope, the full wattage isn't always present unless needed. So, if the system needs 322W and the system is rated for 350W, great you got it. But, don't expect that to be always the case on a constant basis, meaning sustaining rating value isn't a given, its only for peak usage which will vary as the norm. However, if the norm becomes too much demand to handle, then expect a degrading of the p/s unit sooner or later. Thus, a higher rated p/s will supply its rated values for a more sustained time and be "stable".
I've always suggested a decent 400W or better is very good, by the brandname, Enermax, Vantec, Antec, and maybe Forton(sp). Check the cpu support website for p/s unit models "approved" for rated cpu usage, like Intel 2.4Mhz, etc..