I would totally recommend the Sherpa roof rack. When I first installed mine, I didn't have my light bar installed for a few weeks. Mind you I didn't do a lot of driving, but I don't recall any wind noise difference between having the light bar installed or not.
If your planning on getting a light bar, I would just get the fairing with the cut out.
As far as light bars, I bought the ExtremeLED 40" dual color light bar as part of a combo, direct through Sherpa. It's cool having both white and amber but you can get a standard light bar. Really just depends on your budget. I had a Heretic Studio 20" light bar on my Tacoma. Super high quality for the price.
As far as wire tucking, I have some wires going tucked against the seal and secured with a strip of gorilla tape on the passenger side. On the drivers side, I used a KC wire hider seal, which is pretty slick:
KC Wire Hider
I have not mounted a gas tank up there yet. I do have a Rotopax 3 gallon tank that has never leaked on me. I just haven't tried mounting it on the roof yet and not sure I will. To much weight on the roof.
If I know I will be doing some extreme off roading, I will skip running my RTT and either sleep in the 4Runner or use my ground tent and I would be concerned about tipping over. Here's my setup for extreme wheeling.
Was actually pretty glad I didn't have my RTT on when I was last at Tuttle Creek, KS. I kind of got into a pickle.
__________________
RCI Armor, CBI Bumper, WARN EVO winch, Triple Lockers, Sherpa Rack, MR312 Wheels on MT Baja Boss Tires
Build Thread: https://www.toyota-4runner.org/4th-g...der-build.html