wireless n router

I currently have a linksys wrt54g and i am planning to get a wireless n router. So i was wondering since i have an xbox 360 which can only use wireless g,if i use mixed mode and use wireless g for my xbox will that lower my macs connections to wireless g or would i still be able to use the wireless n speeds on my mac.

Nope it shouldn't affect it at all.

oh because i heard that it bumps down your speeds to wireless g for everything