Router: Stateful Vs. Stateful packet inspection(SPI)

Hi, I'm sounding to purchase a new router mainly for my PS3 system but I'm wondering about which router to get. If I purchase a router next to SPI (Stateful Packet Inspection) Vs Stateful feature would I be compromising rate for security or would degradation of speed metal little?:confused ...

Source: http://forums.majorgeeks.com/showthread.php?t=267585&goto=newpost