if you're planning on having people ooh and ahh at the badassery of the terrain you're wheeling, do *NOT* use the wide settings, move to narrow, at whatever resolution you can support on narrow mode. the reason being is that the hero3/3+ have a fish-eye lens, made to capture 170-180 degrees of viewing angle, when you compress that onto a flat image like a tv or monitor, you have a LOT of image manipulation, for examples, go back and find the thread in which I posted the videos from the last meet & greet we did up here in amarillo, there's a spot where I sat back to watch Mac pop up a set of rocks, and, if memory serves correct, it took him a couple tries, nothing major, but, it's a little ledge that's about as tall as the center-line of the wheel, except, in the image, since it's 170deg of vertical viewing angle compressed into a flat plain, it looks like he's having trouble getting over something that's shorter than a parking space "curb" or "bumper" or whatever you choose to call them.
Audio: either get an external mic and a case that'll seal around it (make sure that mic is waterproof too) or, accept that with the water-tight case, your audio SUCKS. it's ok, really, you just have to know it in advance.
Mounting: the suction cup mount is nearly impossible to pop loose unless you hit it pretty hard, or, didn't get a good suction...I have no problem slapping it to the outside of my windshield in front of my rear view and wheeling it pretty hard, which, I must say, is fun. having it mounted on my hood was cool too, but, now that I've bedlined my hood, no more suction mount option there....
