Cool, thanks! I'll work on that RPG... It's been on my list of things to pick up for some time now although I have yet to see any choppers over my neighborhood in the last 6 years. lol As far as the outside wall goes, my lights(cabinet) wont be on an outside wall but I do plan to vent behind the wall that it will be against into some dead space that would actually be closer to my roof than anything else. The air will be traveling through a carbon scrubber, the fan itself, a muffler and then about 10 feet of schedule 40 6" PVC pipe before making into any actual space though.
Thanks again for the info!