although i dont own a xbox...

but here to clarify things...

from the wireless adaptor to the router it only take 1ms or less....

thus it makes no difference when comparing with cable (unless you tell me you can see 1ms difference)

secondly your stremyx speed is 1mbit... or max 2mbit (for those who is lucky).

even with wireless 802.11b, the connection is 11mbit....

in conclusion, YOU SHOULD NOT SEE ANY DIFFERENCE between wired or wireless controller/router