I don't know who told you that, but 550w is plenty for your rig.
Get a better power supply.
When he said "better", he meant get a known brand that won't ignite when you turn it on.
On the flip side of that, getting a slightly more powerful power supply would make his machine a bit more 'future proof'. If he is a beginner at installing computer hardware, it would save him some trouble having to buy and install a new PSU whenever he wanted to upgrade, thus making him less error-prone. He could possibly save some cash as well if he ever decided to upgrade. Whoever told him that is intelligent indeed.
Sorry for the bump, but I still would like to know if this is all compatible. And, is rush delivery worth it?
Getting a better PSU would require more money, which he doesn't have. The 630w he originally had picked out wasn't nearly as good as this 550w. Going down in wattage is, in this case, doing a better job of future proofing his machine.It will all work. Rush delivery isn't needed.
It's Newegg, you'll get them in like a week.