2 Routers, 1 Network, Dual Band, Bridging, and WDS!

I will start by apologizing for my noob questions, but networking is something that still really confuses me to this day - the information all seems so broad and full of variables that there never seems to be clear-cut answers. So, here is my hardware and some background.

Cisco/Linksys E3000, Simultaneous Dual-band router
Netgear WNR2000 Wireless N router
Linksys WRT54G, already flashed to DD-WRT
Old Netgear router, unsure of model

What I wish to do is have my main router, the E3000, upstairs. I then wish to setup the WNR2000 downstairs to hard connect my DirecTV and Xbox 360.

I already did this with an older Netgear router and the WRT54G (the flash to DD-WRT was a pain, but I managed). It worked, but I always had a lot of questions about how well it was working.

1. Is the proper term for my desired setup a WDS?

2. Would the downstairs WNR2000 become a wireless bridge? Or repeater? Is this router capable of what I want it to do? Is a 3rd party flash required, or is it capable out of the box?

3. Can I or do I even need to turn off the wireless OUT on the WNR2000 and just have it wireless IN from the E3000 to avoid any interference or messing with my dual-band connection?

4. Does this proposed setup mess with my ability to utilize the E3000's dual-bands?

5. Does this proposed setup lack in security?

6. Once bridged, would devices hard-wired to the WNR2000 downstairs be capable of receiving up to 150Mbps speeds?

Thank you in advance for humoring my many questions!