OCZ has some great PSUs, good PSUs and some low end PSUs. They're one of the manufacturers that you have to know which PSU and then check reviews. Modstream is low end, StealthStream is mid range, GameStream, EliteStream and Evostream get good reviews. The GameXStream you listed is a good PSU especially for the CAN$ price. In short terms i'd agree with Zorg and run what you have unless/until you have stability problems and then change the PSU.
I will definitely give it a try, but it seems like I will just be making another trip to the computer store to pick up the bigger PSU. Not that it really matters since it's only a 5 minute drive
Do you think it's even possible for a 450W ModStream to support those specs? It's low end as listed in the tiers and low watts. The other guy suggested I need a 720W PSU, I really doubt my old 450W will hold up, but nonetheless it's worth a try.
If anyone has any other opinions please feel free to add. If my 450W doesn't hold up, what is the minimum watt PSU I should buy?