Might want to do some research...
The k&n FIPK (or whatever it is) cold air intake for the 3.4l (tested in 4-runners) actually decreases HP. This site
http://www.gadgetonline.com/4run.htm Awesome Supercharging Page 3.4 L has TONS of info. The guy has done everyting, including making over 300 HP from his supercharged 3.4l He has run many dyno's and found the K&N unit to decrease HP. Cutting a hole into the air cleaner or removing the elbo allowed for the greatest increase in power. Now I know this is the 3.4 and not the 4.7 v8. But you might want to check around to make sure the same isn't true or similar.
Good luck.
Todd