Your vendor is flat out wrong. With that much stuff you'll need a bare minimum 350W unless you are fond of kernel32 errors and warm reboots. Even with 350W you'll get some random crashes. For no random crashes, errors, and constant need to reboot your computer, go with a 380W minimum.
As for specific specifications, look for a power supply that delivers more than 12 amps on the 12V line and at has at least a combined 200W possible on the 3.3V and 5V lines. A good PSU will also have PFC (power factor correction), allowing it to deliver stable flow.
Amperage looks very good, only slightly less than the Enermax/Antec units. It should be able to run anything you throw at it, but you won't be able to use peltiers, OC your FSB to 200Mhz, or daisy chain 5 USB devices to it like you can with other PSU's.
If you just have 1 or 2 hard drives, a few case fans, a fast CPU, and a bunch of add in cards you should have no problem.
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