I had a Dynomax muffler pretty similar to that one on my last car, a 190e 2.3-16 Mercedes, and I did not care for it. I know its not a 4runner so results may be different, but to me it muffled all the wrong frequencies, and ended up sounding odd. The second one you listed will definitely be louder, as its a straight through, where as the dynomax is a turbo style with baffles that slow down and quiet the exhaust. I also think the second one would sound better, it just might be a bit loud
EDIT: Just realized that those dynamax's are straight through. Both are pretty similar mufflers in the end.