Tires, lift are mandatory, but nothing too big, 2" and some skinny 32's would look awesome.
I agree with everyone else, but instead of keeping it as stock as possible, I say keep it as stock or factory looking as possible. Build it, but make the accesories look like they were built with the 4runner, not for it. There's also the option of having them hidden, especially in the interior. An example would be mounting comms inside, with the radios under the seat or inside a console. Same for an aftermarket stereo, additional power outlets, etc.
That is one clean 4Runner, really nice find. Im jealous. Can you post more pics/details???
Cheers,
Luis