I think it will look great with a stock bumper like in the pictures. With my bumper, it kinda looks borderline stupid. Aftermarket bumpers tend to make all side exits look stupid (with the exception of the high clearance side exits like magnaflow). I actually bought this exhaust mainly for the exhaust dump and that it uses the super touring muffler that tanabi is pretty famous for. I figure this is a win-win.
The tanabi sound is very distinctive (very deep bass). If you boobtube Tanabi touring medallion on lexus's you will get a very good idea of how the Tanabi will sound on the 4runner (youtube fails to capture the bass but rest of the sound is similar). It burbles at start up and then goes silent. It has a deep bass sound when accelerating and at WOT, but is barely audible at highway speed or cruising speed. It definitely is louder outside of the cabin than when listening to the exhaust inside of the cabin.
In a few weeks, i'll give the down pipe/ exhaust dump a shot and see if it changes the sound. I had a exhaust dump on my tundra, and it didn't make much of a sound change unless i was at WOT and standing outside. It was loud enough to scare the crap out of pedestrians to walk faster at cross walks (i didn't do it on purpose, i was trying to beat left turn lights). The exhaust dump is super easy to change in and out. Tanabi put a flange from the axle back, so you don't have to lift up the vehicle to change out the tailpipe.
Hopefully, my answers helped answer some of your questions.
Cheers.