This power supply has no regulatory approvals
That says all you need to know right there... $200 for THAT? Um, ok....
Anyway, no, just no.
A good 400W unit would be enough for the 550 Ti.
Let's try this: Antec NEO ECO 520C 520W Continuous Power ATX12V v2.3 / EPS12V 80 PLUS Certified Active PFC Power Supply